Atlantean Cavalry

The trigger is the whole design conversation here: not "when you draw a card," but specifically your second draw each turn. That clause turns a serviceable 3/2 with vigilance into a payoff for a build already stacking card-advantage engines, cantrips, and repeatable draw. A single extra draw beyond your natural draw step grows it once per turn, so the counter accrues at the pace of your engine rather than your mana. The vigilance is what lets those counters matter on both axes at once: the body keeps swelling while staying back to block, so an incremental clock doesn't cost you your defensive footing. It rewards the sort of blue deck that treats drawing two as a baseline rather than a splurge, and it punishes nothing about that plan; the growth is a rider on the cards you were casting anyway. The ceiling depends entirely on how hard you can lean into second-draw triggers, which is the kind of deckbuilding tension that makes a modest creature interesting: the stat line on the page is a floor, and everything above it is a function of how much your list already wants to draw cards.