Puffoxin
Ventokaizer
Viridizaurus
Esapizeron
Gigarex
Clocknight
Scorpionite
Nebelronix
Novatusk
Siegewhale
Ninjastorm
Vulcarexor
Fireheart
Statikat
Flarevern
Omegasdragon
Hate that puffoxin
I just let it kill itself with reckless attack
Lucky guy, it just poison gases me no matter what 
this is when Knock back becomes useful with death revenge monsters
By far one of the easiest “extreme difficulty” challenges
This is just stupid poison abuse challenge. Another broken part of the game
It was easy i bet it on my first try with a random team
I combined the info here with my own. Here’s the line up and most of the monsters’ moves:
http://neomonsters.wikia.com/wiki/Challenge_I%3A_Venom_Legion