Waveform Captain

{u}: +1/-1 or - 1/+1 until end of turn.
{u}{u}: Exile Waveform Captain until the beginning of your opponent's next end step.
Whenever Waveform Captain deals combat damage to a player, create a 1/1 blue Elemental token.
Devoted {u}{u}{u}{u}{u} - Elemental creatures
you control get +1/+1 and are Unblockable.