I think its eggs
They're not. It's small, brown, and hard (considering the amount of damage you can do).
I think they're rocks, for me it doesn't sound like a splatting sound, more like a rock hitting something.
Last time I checked, rocks don't stick to things when I throw them at an object.
They look like big spit balls to me O.o
This is the most likely out of the three, but they'd have to be extremely hard spitballs.
