How to cure an almost 4 year old's temper tantrum

So, Ryan is sick and pitiful, thus making it impossible for him to act like a human boy. For one thing, I can't call him Ryan, but only "sweet angel baby" until told otherwise. His temper (not fever) is currently off the charts.
We were painting ornaments to give people the other night when Ryan starts screaming at his friend for accidentally bumping his paint tray. No mess was made and the tray barely moved, but Ryan felt this still required screaming until his friend was crying, I was yelling, and he was almost purple in the face. We calmed everything down and decided maybe we should just stop the painting for now. We're all cleaning up when Ryan yells he doesn't want to clean, he doesn't want to be near his friend, he doesn't like anybody. I told him I understand he doesn't feel well, but there's no reason to act like a rude brat, and that he needs to stop or Santa will find out he's being naughty. Well, he goes into an almost-four-year-old-tirade about how he doesn't care if Santa finds out.
So...
I did what any sane mom would do, I picked up the phone and "called" Santa and told him Ryan was being naughty and that he didn't want anything but sticks and rocks for Christmas, but should he change his mind I would call him back and let him know.
Ryan got very quiet and said, "But Mommy, I do want my Christmas. I'll be nice." Now, all we have to do to end a tantrum is look at him pick up the phone and say, "That's it Ryan, I'm calling Santa."