Delve: Fungal Folly
Story: Oversparked Operation
End boss: Maulspike
Transcript: Fungal Folly, Oversparked Operation.zip

Apparently people in the wowhead comments section are struggling with this boss, but I might have killed him too quickly to record useful data.

Abilities:
Aggravating Growl - can be interrupted. Increases attack speed.
Rip and Tear - uninterruptible bleed
Whooping Rally - summons adds. Wowhead comments claims the adds can fear, but I killed them way too fast with the Pacifist Rig to find out.

Screenshots: