Spellsteal trick that can be taken into instances

The mobs "Abyssal Flamewalker" in the Isle of Quel'Danas have a buff called "Immolation".

This casts an AOE damage spell which can be spellstolen. This ticks for about 10% of
your spellpower every few seconds.

There's been some debate about whether spellsteals constitute "working-as-intended" or
exploits. In this particular case there's little doubt Blizzard tried to nerf it and screwed up,
the buff doesn't work in-world but does when you take it to an instance.

Spellsteal buffs have only a 2 minute duration but this is a nice little dps boost while it lasts.