Thank you!
I weighed him last night and he doesn't seem to have gained any weight since his last vet visit earlier this year. But he does look so fat! LOL Maybe that's just me looking for a reason for his recent behavior.
But I have not seen a failed attempt at a jump since this weekend. So maybe he was just having a bad day. I heard him in his room this morning playing with a chirpy thing that came out of a toy mouse. So I think he's just fine.