the one story i know, which im not saying is correct, is that a guy had a pair of burms he was breeding in the same enclosure (ofcourse). he supposedly had a male BP that he didnt have anywhere to put, so he threw it in with the two burms as a temporary enclosure, and the male bp and the female burm breed to make burmballs. i have no idea how accurate this story is, but its the only one ive heard, idk about the egg size or anything else though