Grunk

When Grunk enters the battlefield, all Mammals under your control gain the Tamed ability

Mammal Rider: Grunk can crew any Mammal of size Medium or higher, granting Vigilance and +2/+2 to the crewed creature

Whenever an opponent gains life, roll a d6. If you roll a 5
or higher, level up Grunk

"Yo bro what does this dinosaur do?" -Grunk

"Don't punch that Bronto!" -Human