A long time go far far away (ok only like 5-6 years ago) there was a zombie that was different from all the other zombies and it was called the CAVEBAT and he looked like this
Now, he is pretty much the only zombie that can fly in all of R2D series and his job was to take care of the survivors who liked camping on top of buildings, billboards, and cliffs. and he would shoot these little white darts at players and they would take damage obviously since tanks now know as brutes did not have clubs to throw.
Now, this little guy could be hard to kill with just a gun so the flamethrower aka the old version of flamey was the best option to killing these pesky little pricks.
Despite the hate they got from survivors they were very good at taking care of campers and abusers since they could just fly out of spawn and being the smallest zombie of all time making them hard to hit with bullets.
Now with all the farming,camping, and camping on top of roofs where it is hard to get as a normal zombie or any zombie matter fact I think PR should consider bringing this guy back to the zombie herd and I think he should be immune to the boobuster but thats just a suggestion.