Poseidon

Indestructible, must be cast with 7 islands.
{u}: +/- a tidal counter from a target. If without Tidal, it gains Tidal 1. You may +/- a Tidal ability by 1. Permanents gaining Tidal have your choice of +1/+1 or -1/-0 per tide counter.
{u}: Return target creature with 2 or more tide counters to its owner's hand.
{u}: Replace "hand" with "top of library" for a card you control until end of turn.
{u}{t}: Destroy a permanent with 5 or more
tide counters.