118.6. Damage marked on a creature remains until the cleanup step, even if that permanent stops being a creature. If the total damage marked on a creature is greater than or equal to its toughness, that creature has been dealt lethal damage and is destroyed as a state-based action (see rule 704). All damage marked on a permanent is removed when it regenerates (see rule 701.11, "Regenerate") and during the cleanup step (see rule 514.2).
Quote from uncertaintyIf I lightning bolt my opponent's craw wurm during his upkeep, is his worm effectively a 6/1 until the end of that phase or the end of his turn?
When is the damage "removed" (is that the correct word?) from the wurm?
Similarly on my turn, if I attack with raging goblin and he blocks with his craw wurm, could I earthquake for three damage during my second main phase and kill his craw wurm?