There are "sports" where the rules change during the game. Last year, in a "game" of mathematics, this is what happened to yours truly: the "height of the rim" was gradually increased and his contribution did not warrant co-authorship (as initially promised), but only thanks (here, on page 17). Thus, he lost (probably forever) the opportunity to "slam dunk" an Erdös-Bacon-Sabbath number of 10 (=3+4+3).