Transformers Prime Episode #7 Scrapheap

The Autobots discover a cybertronian Pod deep in the Arctic which contains a swarm of metal-eating robots called Scraplets. The scraplets infested the Autobots headquarter, badly damaging the Ground Bridge. Not only do the Autobots have to keep themselves from getting eaten, they also have to repair the Ground Bridge, or else Optimus Prime and Arcee will freeze to death.