I have seen Ragnarok kill and eat a medium rat when he was still a sub-adult/adult size. It was amazing. He had to use his entire body from tip of the tail to his head to wrap around and constrict the animal! He shoved it in his piehole, and his neck stretched out to ungodly proportions!
The most amazing part, was that these were live rats he was taking out! I know some will say it was dangerous, that the rat could have injured him and it was over-feeding, but I didn't know better at the time....and GUESS WHAT? HE KILLED IT AND ATE IT JUST FINE.It was a bit extreme though, probably 20% of his weight at the time.
I don't do that any more, lest the rat bite a hole in my snakes.