15 Times MCU Heroes Actually Killed

9. Baby Groot Blew Ego Up - Guardians Of The Galaxy Vol 2

Having missed out on becoming a true killer in the first Guardians movie on account of being dead himself, the second incarnation of Groot was clearly more in tune with his bloodlust. How else do you account for the thumb he magics seemingly out of nowhere?

Anyway, as Peter Quill works out his daddy issues in the most blatant manner - fighting his actual biological father while the one who raised him runs to his aid - Baby Groot defies all expectations of him as a danger by successfully getting Rocket's bomb into Ego's brain. And even as Ego pleads with Peter to save him and not sacrifice his God-like powers, the little tree man sets off the device and destroys his brain.

As kills go, the youngest hero managing to take down an actual Celestial is a pretty impressive achievement.