So i want to share what i have found out today, i had task for Mukla to use his third ability 12 or 10 times, but it has a cooldown. In the middle of the fight i had Cookies fish as last enemy minion, and i thought that i will win instantly but i didn't, so i used this to spam Muklas third ability until i finished the task, as fish just skips the turn. I am not sure if this i old news, but there, maybe it helps someone.
Yeah, it's good for completing most - though not all - tasks (Could probably work most of the others using Anacondra to buff the health of one as you summon others, but would be slow). No clue why it's not considered a trivial minion, like totems and other summoned 0-attack ones.