This is a bizarre story that can make one wonder about the sanity of researchers, but at the same time it’s interesting.

Bees will apparently form a bee ball around hornets in order to kill them. How?
a) It heats them up and
b) It increases the carbon dioxide until said hornet is dead.

To research this there was taping of hornets in spots that would get them killed, then measuring the heat and carbon dioxide levels inside the bee balls.