Incognitro, the Indecipherable Felcycle

PART 1
Complete Azeroth's Greatest Detective achievement - the fastest way would be to complete No Crate Left Behind as it also grants Crate Insurance Agent

Equip the Detective title and talk with Dalaran Survivor in Dornogal to start the quest.
/way #2339 54.99 28.92 Dalaran Survivor

Find the clues to the Ratts' location in Azj Kahet:
Note 1 - Enter the cave, the note can be found inside the circle of fungarians.
/way #2255 69.34 93.32 Unfinished Note

Note 2 - On the ledge overlooking the City of Threads.
/way #2213 31.49 20.75 Hastily Scrawled Note

Note 3 - Between Hallowfall and Azj Kahet. Enter the hidden cave above Azj Kahet grounds. The note is found at the bottom of the lake.
/way #2215 50.73 86.64 Water-Resistant Note

Ratts location
Enter the cave, find steps on the wall and jump into the middle hole to enter a hidden room. Confront Ratts and you'll get the Peculiar Gem on the ground.
/way #2255 55.03 19.09 Cave Entrance
/way #2255 56.38 17.42 Hole

Inert Peculiar key location
Travel to Un'goro Crater and loot the key using Torch of Pyrreth
/way #78 44.55 7.98 Inert Peculiar key

Click on the Inert Peculiar key in your backpack to turn it into the Peculiar key. This will allow you to enter the Karazhan catacombs using the side door. Use the Torch if you can't enter the instance.
/way Deadwind Pass 46.65 69.03

Exploring the catacombs will lead you to the mount standing in the middle of the room with pylons that need activating.
/way 68 25

1 O'CLOCK PYLON: LOVE
Use the Torch of Pyrreth at three locations to gain 3 stacks of The Light of Their Love. Stand at each location and wait until the buff stack goes up. Can be completed in any order. Nagrand's Olgra can be found in one of two locations.

/way #10 55.0 40.2 Humble Monument, Northern Barrens
/way #550 74.2 37.5 Olgra, Nagrand Draenor
/way #550 49.2 48.0 Olgra, alternate location
/way #1536 27.3 61.3 Decimator Olgra, Maldraxxus

2 O'CLOCK PYLON: PRAY
Required items:
Perky Pug
Perky Pyg costume - either "Yipp-Saron" Costume (acquired from Hallow's End) or "Dogg-Saron" Costume (sold by Vashti the Wandering Merchant for 25,000g)
One of the three: Twitching Eyeball or All-Seeing Eyes toy or wear Gift of N'Zoth
Gift of N'Zoth and Twitching Eyeball can be obtained from Crucible of Storms questline that starts with The Azsharan Medallion looted from naga during the active Naga Attack! world quest in Zandalar/Kul tiras

Obtaining the Key of Shadows:
Head to Vale of Eternal Blossoms and find the Ny'alotha obelisk above the Seat of Knowledge (roof). You need to be in the BFA phase.
/way #390 83.6 27.5 Obelisk in Vale of Eternal Blossoms

Summon the Perky Pug, put on the costume and use the toy.
Target the Obelisk and type /pray
Wait a while and the key will appear in your bag.
*SKIP* If anyone in your group or the same area completes these steps, then EVERYONE gets the key. This means you can ignore all the steps, go to the Obelisk location, and wait for someone who meets the requirements.

Remove The Light of Their Love buff from the previous puzzle if you still have it.

3 O'CLOCK PYLON: HATE
Open the Chamber Door in the Karazhan catacombs using your Key of Shadows.
You will see the Astral Soup on the shelf. Fish in the bowl to loot the Astral Key - requires a few attempts. Open the Astral Chest and loot the Starry-Eyed Goggles.
Interact with the Decryption Console, enter the code 88224646 and then press submit. You'll be able to open the "Property of Elder Ko'nani" (right next to the console) and loot Piece of Hate.
Equip the Starry-Eyed Goggles to look for other Decryption Consoles in the catacombs. Enter the code and open the chest next to the console. If you can't see the numbers on your main action bar, interact with the console (don't move) and open Spellbook > General > Number Sequences Spell

/way 68.1 83.3 19019
/way 56.1 62.1 5661
/way 49.4 65.0 10638
/way 49.6 80.3 88224646
/way 42.8 70.9 17112317 - Encrypted puzzle box on the table
/way 65.0 48.8 52233
/way 70.4 54.5 51567
/way 68 25 anywhere from 777 to 777777777*
/way 66.2 15.6 115

*If you're using the correct sequence of 7s, you'll see the magnifying glass above your character. It can take several attempts though. You'll get the Piece of Hate straight into your bag when successful.
7 Lucky items increase the chance of getting the Piece of Hate from this console:
Lucky Charm - Lenny "Fingers" McCoy
Lucky Dragon's Claw - Griftah
Lucky Duck - Lilistrasza
Lucky Horseshoe - Farrier Roscha
Lucky Rat's Tooth - Lenny "Fingers" McCoy
Lucky Shirt - Lenny "Fingers" McCoy
Lucky Tortollan Charm - Griftah

/way #84 72.8 58.8 Lenny "Fingers" McCoy
/way #2339 62.6 50.8 Griftah
/way #2023 84.4 25.0 Farrier Roscha
/way #2022 59.8 70.4 Lillistrasza

4 O'CLOCK PYLON: DOOM
Buy Scroll of Fel Binding from Vashti the Wandering Merchant in Azsuna.
/way #630 66.0 22.2 Vashti the Wandering Merchant
He's travelling down this path.

Travel to the Uther's Tomb in Western Plaguelands
/way #22 52 83

Use the scroll inside the tomb to summon a doomguard
While the doomguard is present, four red runes appear around the statue. Using the scroll killed me, but when I released the Doomguard appeared again allowing me to interact with runes.
Read them all to light the 4 o'clock orb.

/run print(C_QuestLog.IsQuestFlaggedCompleted(84780))

PART 2 IN THE COMMENTS

PART 2

5 O'CLOCK PYLON: MUFFIN
Get Zarhym's buff in Timeless Isle, Cavern of Lost Spirits
/way #554 45 36
Find Jeremy Feasel in the same cave at /way #554 43 39. After entering the Spirit Realm, don't loot anything or find Zarhym Bones, as you'll be put on a daily lockout for talking to the skull if you do.
You need to have the 4 O'clock Pylon lit, otherwise Jeremy Feasel will not offer the quest.
Defeat Jeremy using a party of only secret level 25 battle pets.

Recommended "Secret" Pets
Spyragos
Nelthara
Wicker pup

Current Confirmed "Secret" Pets
Terky
Gurgl
Glimr
Snowclaw Cub
Jenafur
Bumbles
Sun Darter Hatchling
Baa'l
Taptaf

After defeating Jeremy properly, he starts Master of Secrets quest, which awards the Golden Muffin
9 Pieces of Hate and Golden Muffin can be used to buy Relic of Crystal Connections from Pointless Treasure Salesman inside the Goblin Statue in Booty Bay.
/way #210 35.56 63.46

6 O'CLOCK PYLON: ALTARS
OPTIONAL: Target the Humming Crystal through the gate and use the Relic of Crystal Connections to phase through the gate to enter the room in the Karazhan catacombs. Target the crystal above the outside of the door to leave the room.
/way 70.6 45.9

Go to Zul'Gurub and find 5 Altars of Acquisition
/way #50 78.24 43.99 Sin
/way #50 77.47 43.93 Corrupt
/way #50 77.05 44.88 Succubus
/way #50 77.08 46.31 Blood
/way #50 78.14 46.31 Void

Each altar needs a combination of a specific pet, toy, transmog and/or mount and a Torch of Pyrreth. If correct, you get: The spirit departs, satisfied with your acquisitions.

Sin

Corrupt

Succubus

Blood

Void

Pet

Sinheart

Any pet with "corrupt" in the name

Sister of Temptation

Any pet with "blood" in the name

Lesser Voidcaller

Toy/item

Bondable Sinstone

Ring of Broken Promises

A Steamy Romance Novel

Throbbing Blood Orb

Void Totem + Shadowy Disguise

Transmog

Any sinstone back cosmetic

Cloak that shares appearance with Cloak of Overwhelming Corruption

Hidden or go naked

N/A

Cloak that shares appearance with Cloak of the Black Void

Mount

N/A

Any mount with "corrupt" in the name

N/A

Any mount with "blood" in the name

N/A

.

*SKIP* If any one player has the required items, all other players (with their torches out!) nearby will also get credit.

After completing all five altars, a spectral Chest of Acquisitions will appear at /way #50 78.1, 47.7
You need to have the 5 O'clock Pylon lit, otherwise you won't be able to see the chest.
Open the chest and loot Ancient Shaman Blood.

Use this macro to check progress:
/run for i,a in ipairs({"Sin","Corrupt","Succubus","Blood","Void","Chest"})do print(a,C_QuestLog.IsQuestFlaggedCompleted(84805+i))end

7 O'CLOCK PYLON: WATCHERS
Acquire the Fledgling Warden Owl (vendor or AH). Summon the owl and get all four buffs from the Owls of the Watchers in Azsuna (blue, green, red and purple) by standing near the statue. Once buffed, you'll get the magnifying glass above your head, your pet will fly around the statue and glow in the specific colour. Once your pet has all the buffs, it'll have a white/purple orb above the head. If you see 'You can't do that yet' when interacting with the statues, you have to fly around and look for the active ones. Enable steady flight so you don't lose your owl.

/way #630 44.18 72.41 Owl of the Watchers A
/way #630 40.54 73.15 Owl of the Watchers B
/way #630 40.52 75.19 Owl of the Watchers C
/way #630 37.10 82.16 Owl of the Watchers D
/way #630 43.24 85.30 Owl of the Watchers E
/way #630 43.66 87.51 Owl of the Watchers F
/way #630 50.45 91.67 Owl of the Watchers G
/way #630 47.48 84.74 Owl of the Watchers H
/way #630 45.97 84.06 Owl of the Watchers I

Enter the Vault of the Wardens solo on any difficulty at /way #630 48.1 82.1
Summon the Fledgling Warden Owl and defeat the first boss Tirathon Saltheril. This open a secret room with 4 orbs circling around at /way 19 78 - go back to the dungeon entrance but instead of turning left, turn right
Make sure they're present, take the elevator to the second floor and defeat Inquisitor Tormentorum, Ash'Golm and Glazer
Take the elevator to the lower floor and pick up the Glowing Sentry to kill the Spirit of Vengeance guarding the final door. Pick up the orb on Cordana Felsong's platform and defeat her. Take the orb back up two elevators to the secret room. If done properly, a Sentry Statue appears in the centre of the Secret room. Loot it and return to Glazer's room. Place it on the flat platform under the stairs as you enter the boss area.

*SKIP* At this point, other players can join the party to get credit.
Interact with the Sentry to start the puzzle. You need to find the correct pattern to hide them all. Each statue is linked with four others. Resetting the puzzle will reset the links!
Follow the steps here: https://ham.io/watcher-solver/ Owls on the tiles must be facing you, go to the far right side of the puzzle.
With all statues hidden, the Treasure of the Wardens chest will appear where the Sentry Statue was placed. Equip the Starry-Eyed Goggles to see it. Loot the Warden's Mirror to complete.

PART 3 IN THE COMMENTS

PART 3

8 O'CLOCK PYLON: STATUES
Go to the Karazhan Catacombs and deposit Ancient Shaman Blood and Warden's Mirror into the Enigma Machine /way 59.9 43

<Fill the arcane catalyzer with ancient shaman blood.>
<Insert the Warden's Mirror into the lightbox.>

Interact with the machine again and <Pull the "BEGIN" lever.>
An emote appears: The dungeon echoes with the sound of mechanisms resetting. The seven pressure plates scattered around the catacombs light up.
Then <Pull the "SUBMIT" lever.>
If you've been interacting with the machine and platforms before, reset the instance - exit the dungeon > right-click the player frame > "Reset all instances" - and repeat the above.
Pulling the SUBMIT lever spawns several rat critters (not the existing Catacombs Rats). You must COUNT ONLY Rats but kill all rats (including catacombs rats) across the instance so they don't accidentally run over a pressure plate.
The number of rats corresponds to the number of entities that must be placed on the platforms. This is primarily statues but can also be triggered by the player, pets, certain toys etc. The pressure plates will show different colors based on the number of entities on them: 1 - Blue, 2 - Green, 3 - Yellow, 4 - Orange, 5 - Purple.

Count (and kill) the rats and follow the instructions for Lock 1. Pull the submit lever - if correct, the magnifying glass and an emote appear: You hear a mechanism unlock. Count and kill the rats that spawned again, and move all statues off the platforms. Follow the instructions for Lock 2. Pull the submit lever. Rinse and repeat until you get 3 locks opened. If incorrect number of statues is placed, the player will get zapped and have to start over from the first lock. Whatever you put on the platform has to be there when you pull submit lever.
*edit* The number of locks has been nerfed from 7 to 3

# rats

Lock 1

Lock 2

Lock 3

1

1 on P1

1 on P2

1 on P3

2

1 on P2

1 on P4

1 on P6

3

1 on P3

1 on P6

2 on P2

4

1 on P4

2 on P1

2 on P5

5

1 on P5

2 on P3

3 on P1

6

1 on P6

2 on P5

3 on P4

7

1 on P7

2 on P7

1 on P1

8

2 on P1

3 on P2

1 on P4

9

2 on P2

3 on P4

1 on P7

10

2 on P3

3 on P6

2 on P3

The Enigma machine will say how many locks are remaining.

Platforms:
/way 71.5 20.2 P1
/way 68.4 32.2 P2
/way 73.6 43.0 P3
/way 68.8 51.0 P4
/way 73.6 65.4 P5
/way 60.3 71.6 P6
/way 47.9 78.9 P7

Statues:
/way 70.41 79.07 Rage Statue
/way 49.47 75.73 Nature Statue
/way 43.48 65.02 Watcher Statue
/way 61.05 47.96 Guardian Statue
/way 70.56 34.44 Greed Statue

To access the platform in the Humming Crystal room, drag the statue to the gate, target the crystal and use Relic of Crystal Connections.

Useful macro to target rats:
/target Rat
/run SetRaidTarget("target",8)
/cleartarget [help]
/stopmacro [noexists][dead]
/ping [@target]

When successful, the 8 o'clock orb will light up and an emote appears: A great lock has been released
This opens the Enigmatic door at /way 68 15

9 O'CLOCK PYLON
Go to the same location where we first confronted Ratts
/way #2255 55.03 19.09 Cave Entrance
/way #2255 56.38 17.42 Hole

Put on your Starry-Eyed Goggles and look up to find the platform with the Humming Crystal
Target the Humming Crystal and use your Relic of Crystal Connections to teleport to the platform
Click the Decryption Console and enter the sequence 84847078 then hit the SUBMIT
The nearby Encrypted Chest should unlock, allowing you to loot Keys to Incognitro, the Indecipherable Felcycle, also awarding you the Feat of Strength Ratts' Revenge

10, 11 and 12 o'clock pylons have a void appearance now. You can now enter the cat room and pet the cats - it seems to work only when you recently mounted the felcycle.
When mounted on the Felcycle you can use the 'Override Sequence' spell in the General Spellbook that allows you to enter numbers - most likely unlocks secret functions of the mount.
17 - Performs a variety of animations at random (green fireworks, green lightning, fel smoke or sound of flatulence)
418 - You turn into a Noblegarden bunny and lay an egg

THANKS TO ALL SECRET HUNTERS FROM WOW SECRET FINDING DISCORD FOR SOLVING THIS

10 O'CLOCK PYLON *unsolved*
Press the Red Button 1000 times. It's located above the Door 430 in the catacombs. You can check your progress by clicking the Scrying Orb to the left.
/way 47.42 67.73

11 O'CLOCK PYLON *unsolved*
12 O'CLOCK PYLON *unsolved*