Servius

"It appears to be magically anchored. The only way to destroy it would be to disenchant whatever keeps it fixed in place. That would be a difficult task, possibly impossible, with the resources we have. If we attack it, we may wipe it clean for a few weeks... but it could be re-occupied at any point. It would be like wiping raindrops off a book while trying to read during a rainstorm - a temporary measure at best."