That's No Ordinary Gas Cloud!

This achievement requires you to use the Dragonflight crafted item Zapthrottle Soul Inhaler to encage 2 of each type of elite elemental on the Dragon Isles. The Zapthrottle Soul Inhaler can be purchased on the Auction House, but if you'd like to craft your own you can get [item=199415] from putting 20 poinnts into the Scrapper sub-spec of Optimized Efficiency.

The elemental you are channeling on needs to die within a short period of your cast ending, or during your cast of the item. Visit the below elementals and use the item on them twice per elemental. You don't need to wait for the 15 minutes for the item to hatch for this achievement.

/way #2022 52.8 30.6 Earthshatter Elemental (Earth Soul)
/way #2023 24.6 36.0 Stormbound Colossus (Air Soul)
/way #2023 55.6 77.2 Force of the Springs (Frost Soul)
/way #2024 78.6 38.8 Fire Elemental (Fire Soul)

Not mentioned by Buuloki, but you also need to buy 8 [item=200938] at AH before trying to capture the elementals.

Zapthrottle Soul Inhaler has a 5 minutes cooldown.

Also, if you cage an elemental of a specific type (like fire), you won't be able to cage a second fire elemental unless you open the first cage containing the fire soul.

Good news, everyone! This achievement title, along with its counterpart Just an Ordinary Gas Cloud, are direct quotes from [npc=36678].