Bubble Trap is a controlling spell from Witchcraft skill set. This ability traps enemy into a bubble and lifts it above. Though the spell doesn’t deal direct damage, target will take damage anyway. When the effect ends, target falls and takes damage from falling. The higher it was lifted the more damage will be dealt.
Don’t forget that the effect of the spell ends when trapped target takes damage from other source. So if someone will deal damage to trapped target in the beginning the bubble will not be able to lift it high enough. This will decrease damage from falling.
List of abilities that can be used before Bubble Trap in order to benifit from Bubble Trap combo effects.