Mischief!

Waffle is In the first room you enter of the dungeon, stick to your right side. Just past the first Banker in the room turning right around the pillar and immediately to your right again you will find him behind a plant.

From here continue out into the dungeon, to your right you will see the first set of stairs. Go down them and then take a left. The cart full of gold and treasure chests in front of you just down the stairs is where you want to turn right. Behind a tree you should see Goblin.

Continue on this path, crossing the bridge where the two Core Hounds are. Keep running forward, and run past the stairs, underneath a tent in the corner you can find Pancake.

From here turn around and go down the stairs. Run forward towards the more open area and stick to the left wall. Enter the hallway to The Grand Menagerie. In this hallway, on your right hand side behind a large wooden-ish crate (with red bands on it) you will find Pickle.

Turn around the way you came, the time turn to your immediate left. Run ahead to where there is a tent and two neutral NPCs standing by. Behind a table with rope and small cages on them, you can find Sassafras.

Start running directly north from where you are. Run all the way across the stairs and PAST The P.O.S.T office, running ahead towards the arches rather than entering the boss room. After you go through the arches, stick to your left. Go down the alleyway that turns left and run just past the portal, there underneath a tent, and behind a bunch of paintings you will find our friend Oswald hidden away.

Here's a picture of all the locations if you dont wanna watch a video :)
https://imgur.com/gallery/JEnS05Z

Hi so no one has said it yet, although I'm sure people have tried without commenting.

you CANNOT get this achievement after completing a streets mythic +.

I went to one of them after the key was over and i tickled one many times trying. no dice!