The Flash, Barry Gordon

Haste, Double strike, Flash,
When The Flash enters the battlefield or attacks, you gain {e}{e}{e}
Pay {e}, The Flash gets +1/+0, (activate this ability only as sorcery.)
Dash, {2}{r}{r}{e}{e}(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.)