Those little rodents would get absolutely shitfaced and turn into total clowns. They'd run halfway up the trunk and lose their grip and fall, or they'd leap from one branch to another and miss. When they sat up they'd wobble and fall over. Funniest was when they tried to leap at the trunk to climb it and would smash into it face first instead.
The tree wasn't terribly tall, and squirrels don't have much mass, so fortunately none got terribly injured, mostly just dazed for a while. We tried to keep on top of cleaning up the decaying plums, but weren't always successful.