At the beginning of your end step, Canyon Crab's ability will check to see if you've cast a spell from your hand this turn. If you have, the ability won't trigger at all. If the ability does trigger, it will check again as it tries to resolve. If you've cast a spell from your hand since the ability triggered, the ability won't do anything.
: This creature gets +2/-2 until end of turn.
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card, then discard a card.
