Grizzly's got a booty like --- POW! POW! POW!
How Daffy Duck responded to the bear's sway-mooning him after crossing over to the other side of the hunting-boundary --- i.e., he was offended by the bear's cheekiness, and so he fired some shots in the bear's direction at the next chance he got.
Shortly after Daffy Duck performed the whole, "Grizzly's got a booty like --- POW! POW! POW!" routine, he did indeed manage to score a glancing hit on the bear's butt and blow off a patch of fur, so the bear vengefully stuffed Daffy's beak full of shotgun-shells and catapulted him through the air so that he slammed head-first into a tree, setting off the shells one by one and causing massive jets of flame to blast out of Daffy's mouth for some time afterwards.