If you un-mount it, you lose it. I guess Jagex did that to prevent people from power training slayer without actually killing anything. Actually you do get back the head when you un-mount it.. same goes for cw armour, metal armour, fish trophy? Swords, Glorys... etc.. No you lose head when you un mount. Dont lie to people if you dont know what your talkign about. Otherwise you noobs would level slayer buy mounting and un mounting it. I suggested to jagex that we would be able to move a mounted head to another room and get 0 xp. I lost my basilisk head when I replaced it with my kbd head. So you sir are a liar and need to stop passing bad info to the community.