A single, very tiny piece of room temperature cotton candy.
It is so small it cannot cause an allergic reaction if ingested, cannot choke anyone, and would not hurt if you were to poke someone's eye with it. No matter how fast speed it reaches, it would be completely harmless on contact or disintegrate before reaching the person. If it were to do some weird thing like go in someones brain, it would just breakdown and be completely harmless. It's a normal piece either, not poisoned or has any weird stuff in it. You're done buddy. It's over.