Cat-Gator

The seven-mana price buys a variable-sized removal spell bolted to a lifelinking body: the enters-the-battlefield trigger deals damage equal to your Swamp count, so the whole payload rides on how many Swamps you can muster by the time it lands. Crucially, that trigger counts anything with the Swamp subtype, not just basics, so shocklands, original dual lands, and triomes that carry the type all feed the number without asking you to run a monochrome manabase. The design's sharpest wrinkle is that the creature itself deals the burst: because lifelink cares about damage this creature deals, not merely combat damage, the ETB shot gains you life equal to whatever it dealt. Point it at a face for five and you are up five, point it at a threat and you clear it while padding your total. That reframes the 3/2 body. It is not a clock and it does not want combat; it wants to arrive at the exact moment its trigger matters, which puts a premium on blink and recursion effects that let you fire the arrival again. The lineage is old: black has long priced payoffs against how many of a single land type you can name, from cards that pump on Swamp count to ones that drain by it. This one folds that reward into removal, life gain, and a modest attacker in a single arrival.