Liliana, The Deviant Queen

Deathtouch
Other merfolk creatures you control get +1/+1.
Other zombie creatures you control get +1/+1.
Whenever another creature is put into a graveyard
from the battlefield, you may pay {u}{b}.
If you do, create a 1/1 merfolk-zombie token with deathtouch.
"The merfolk never truly die"