I'm happy to hear there are some not so bad possibilities. It is definately not a tick. I've seen those more than I'd like to remember and this isn't one. And it doesn't look to me like it could be a bug bite. My guess is it's probably ok. My gut says it came on a little too fast to be my worst fear, and he has plenty of energy and all that. I've been out of the house for 3 or 4 hours now and when I got home dh was out with the pups for a walk, so I'll have to check when they get back. I hope it's gone down some...
I think I was a little taken aback when I saw it because I thought they'd already thrown at me all the surprises they had up their sleeves. Since they are both ten-ish I thought I had seen it all. lol I don't know why I'd feel that way though. About a year ago, I thought he was in big trouble when I woke up in the morning to see that he seemed to not even be able to lift his back end off the floor. It scared me to death, carried him to the car, rushed him to the vet and it turned out it was from the four macademia nuts he ate the night before. D'oh!