Heartstone Unicorn

Trample, lifelink
Whenever Heartstone Unicorn deals combat damage to a player, you may have it deal damage, equal to the amount of damage Heartstone Unicorn dealt, to target creature.
"Majestic as it is deadly, this beast is able to use its magic to cauterize the wounds it deals into crystal fragments and send those fragments back at the prey."
-Tamiyo's Field Journal pg. 97