Sharknado

Sharks you control have flying.
{u}{b}: Sharks you control get +1/+1 for each
Shark-counter on Sharknado until the end
of turn.
{1}{u}{b},{t}: Put a Shark-counter on Sharknado.
If there are 10 or more Shark-counters on
Sharknado, sacrifice this enchantment: Return
every Non-Shark creature to its owners hand.