The character cannot be harmed with physical attacks but is affected by force damage and other non-physical attacks as normal. He may pass through solid objects at will, though force fields and other effects block his movement. This condition doesn’t convey any special ability to float or fly, and an incorporeal character must hold his breath when his mouth and nose are blocked. Should a character lose this condition while occupying the same space as another character or object, they merge and all characters in the merged mass are immediately killed.