There's Always A Bigger Fish

As an additional cost to cast this spell, sacrifice a
Shark creature.
Create an X/X blue Shark creature token where
X is the sacrificed creature's toughness plus one.
That token has "Sacrifice this creature: Create an
X/X blue Shark creature token where X is this creature's toughness plus one. That token has
this ability. You cannot use this ability the same
turn this creature came into play."