It takes Ivar a moment to realize his attack did nothing. The alien instincts understand the attack wasn't successful, so he starts looking around for the real thing. There's a yowl of pain from the alien when Jack sets him alight, but this time, Ivar has enough presence of mind not to panic. Bees he might not be used to dealing with, but he's burned enough people alive to know what to do when he smells his fur on fire. He drops to the ground rather then panic and furiously rolls around until the flames are thoroughly extinguished.

Getting back to his paws, he sees where this nuisance, who has become quite a bigger nuisance then initially anticipated, has gone behind a tree.

He digs his paws into the ground, scuffing dirt up, and then charges Jack. He's not aiming for him though. The Viking is going for the tree. He rams his head and horns right into the trunk. Forget about stomping Jack. He's just going to bring the whole damn tree down on him to pin this tricky man down.