Mutilate

[15bm]

If I cast {mutilate} while I have 6 swamps and my opponent has a {myr superion} and an {adaptive automaton}, naming myr. Does mutilate take out the superion after it loses the buff from the automaton?

[Maximo]

yes.

[15bm]

That's what I thought but thanks for the confirmation

[Gorzo]

Yes. 

Automaton will die, and once he leaves the battlefield, myr superion's toughness will be down to 0 (6 - 6) and will then leave the battlefield himself.

Assuming nothing else buffs its toughness, of course.