In game 3 of the first round of the tournament today, I took my game 2 deck of monotime pharaohs and changed my mark to gravity, thinking my opponent might bring the same creature deck he'd just used. Not only did he use a creatureless deck, but I forgot that half my quanta sources were pendulums, and as a result, I lost 1/4 of my time quanta production to gravity that was completely useless, costing me the game and the match :p
Yeah... not so good with a gravity mark :p Still, as I said in chat, anyone stupid enough to make such a mistake does not deserve to win :p