Somebody Else's Problem field

The Somebody Else's Problem field, or SEP-field, is a device from The Hitchhiker's Guide to the Galaxy that cloaks someone or something by making everyone view whoever or whatever is cloaked as somebody else's problem. They duly ignore the SEP-field.

This handy gadget can be found in flashpatches and can be activated in a PPC TARDIS if the chameleon circuits go haywire.