Ball Python Regurgitated...

[seercirra]

If you can't think of anything that would cause the flight response and saw it go fully down, then the issue may prove to be something that requires a vet, i.e. a blockage. If it came back up completely, it's wait a week then offer the next size DOWN food item from what they're on now. If he does it again, then you're going to absolutely need to schedule a vet visit to look into possible internal issues.

Also double-check your humidity and temps. Something may be amiss.

Could it be caused by being near something smelly in the freezer? Like curry or something?
I'll do what you say, try him something smaller in a week and take him to a vet if the same thing happens. The only issue with that is that he usually goes off feed this time of year until after Christmas. He's never been i'll, he always starts again in January, but he's done it every year for his whole life.. so next week he might not eat and it'll just because because he's off food. I'll take him to the vets if he regurgitates again.