Sonic, Hero of Mobius

Flash, First Strike

When Sonic enters or attacks, put a +1/+1 counter on up to one target creature. If Sonic was cast for its Spindash cost, target creature you control gets +1/+1 until end of turn instead.

Spindash - {r}{g} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)