Here is the wording on his special. Dispelling ends the effect and thus whatever damage is set at the time, hits all of your heroes.
dont like it …
It helps me more often than not because I don’t face the pig often, but use him a lot while raiding.
However, if you kill Gullinbursti before the 3 turns is up, he won’t do damage. I guess killing him doesn’t “end” the effect lol
Death is the best equalizer, lol.