Delina, Wild Mage (LIST-138) [The List Reprints]

Whenever Delina, Wild Mage attacks, choose target creature you control, then roll a d20.

1-14 | Create a tapped and attacking token that's a copy of that creature, except it's not legendary and it has "Exile this creature at end of combat."

15-20 | Create one of those tokens. Roll again.