Its weird I'm sure this is the entrance, and the other side of his head looked unscathed. His eye wasn't even popped on the other side so I'm not sure what happened, distance was close about 27y.
Was the impact the aim point? That slug did some damage for sure. Well done!
Not trying to stir anything but ive been hammering squirrels lately and “brain” shots (in the brain) absolutely shuts them down. No kicking violently and floundering etc. I’ve been killing squirrels for years and years and just recently have found the lights out spot. So satisfying!