Ornif, Sea Devastator

Reach Trample
When Ornif, Sea Devastator enters the battlefield
sacrifice a Merfolk, Mermaid or Octopus
Sacrifice a Merfolk, Mermaid or Octopus Ornif,
Sea Devastator gets +1/+3 until end of turn.
Only use this ability once per turn
Untap Ornif, Sea Devastator only if you sacrifice
a Merfolk, Mermaid or Octopus