Superior slayer monsters are more powerful versions of normal slayer monsters that have a 1/200 chance to spawn upon the death of one of its normal counterparts. They can be encountered after purchasing the unlock Bigger and Badder for 150 Slayer reward points from any Slayer master, and will only occur while on-task. This can be toggled on and off afterwards without loss of points.
When a superior slayer monster spawns, a message will appear in the chatbox, stating "A superior foe has appeared..." Killing a superior slayer monster will reward players with a greater amount of Slayer experience compared to what would be earned from the normal slayer monster. They will also give three rolls on their lesser counterpart's drop table. Once a superior slayer monster has spawned it is only attackable by the spawning player. A superior monster will despawn from the world if ignored for 2 minutes. This is however not the case if you leave the area. In that case, the superior will disappear 
In addition, once one has appeared, another one will not spawn for that player until it is killed or despawns. In single combat areas, a superior slayer monster can be attacked even if you are under attack by another monster; when this happens, the standard monster will stop attacking you. In multicombat areas, it is possible for multiple superior slayer monsters to appear simultaneously if multiple monsters are killed at the same time.
Superior slayer monsters are guaranteed to drop an ensouled head (if applicable) and dark totem pieces (when killing one within the Catacombs of Kourend). Players are also ten times more likely to receive a clue scroll from killing one. In addition, superior slayer monsters have three unique drops shared among all superior slayer monsters:
- Imbued heart, which boosts the player's Magic level by 1 + 10% every seven minutes.
- Dust battlestaff, which when equipped provides an infinite amount of air and earth runes.
- Mist battlestaff, which when equipped provides an infinite amount of air and water runes.
The chance of rolling the unique drop table is 1 in
If the players rolls the unique drop table, there is then a 1/8 chance of receiving the imbued heart, and a 7/16 chance each of receiving one of the battlestaves.
There are superior versions of the following monsters:
- ↑ Twitter - 19 Oct 2016
- ↑ Twitter - 18 September 2016
- ↑ Personal experience from this editor that a marble gargoyle spawned for me, but I was almost out of supplies so i instantly teleported to bank to get some supplies (without attacking it) and then got back but the superior wasn't there anymore. I later tested it with a timer and it proved to be about 1 minute to get back, which leads me to conclude that the superior instantly despawns if you leave the area, or that the 2-minute timer is incorrect.
- ↑ Twitter - 20 October 2016