Weasels. www.bbc.com/news/world-e...

Large Hadron Collider: Weasel causes shutdown - BBC News

The Large Hadron Collider particle accelerator in Switzerland is offline after suffering a short circuit - caused by a weasel.

Too big for the ferrets to deal with. They need a highly intelligent, very motivated larger 4 legged animal who is willing to work for sausages.