A mounted abyssal demon head can be built in the head trophy hotspot of the Skill Hall in a player-owned house. Upon building it, players will receive 389 Construction experience and 889 Slayer experience.
Players can only get the stuffed abyssal demon head by killing Abyssal demons, requiring 85 Slayer, until they drop an abyssal demon head. Players must then take the head to the Taxidermist in Canifis, who will stuff it for 12,000 coins. Once mounted however, the head cannot be reclaimed. If players remove the mounted head, they will receive nothing back. Jagex has stated that this is because mounting the head rewards Slayer experience, and they did not want players to be able to train Slayer by removing and remounting the abyssal demon head.
This article has an associated transcript page. Click here for the transcript.