So, I've never seen it happen, but can you Dash (the ability) in creatures to have "surprise blockers"?
{goblin heelcutter}
Grom the "mechanics of FRF" article (closest I could get to proper ruling):
QuoteIf you choose to pay the dash cost, you're still casting the spell, so it goes on the stack and can be countered. Dash doesn't change when you can cast creature spells—usually only during your main phase. If you cast a creature spell using its dash cost, it will return to your hand only if it's still on the battlefield at the beginning of the next end step. If it leaves the battlefield before that point, it'll just stay wherever it is.
Just add something silly like {prophet of kruphix} and voila instead speed dash blockers.