A basilisk head is a very rare drop from Basilisks, which requires 40 Slayer to kill. It can be mounted in player-owned houses in the Skill Hall with level 38 Construction. This method is a one-time use and the head cannot be reclaimed.
If a player wishes to have the basilisk head mounted, it must be taken to the taxidermist in Canifis. She will charge 4,000 coins and turn it into a stuffed basilisk head. They may then mount it in their player-owned house by using 2 teak planks with the stuffed head.