Atlas, Sizable Stooge

The lifegain trigger here is built to reward a very specific board texture: not a wide swarm of small bodies, but a lineup of genuine bruisers. At four mana for a 5/4, Atlas both qualifies for its own condition and asks you to surround it with creatures that clear the power-4 bar, so the payoff scales with a deck already committed to fat, aggressive threats rather than tokens or utility dorks. The choice to trigger on attacking or blocking is the load-bearing detail: it means the life comes whether you push the game forward or hold the fort, and reach turns those blocks into a credible answer to the fliers that usually punish a ground-based fatties strategy. That combination (big body, defensive keyword, incidental life on both sides of combat) points the card squarely at the sort of midrange golgari build that wants to grind an opponent out through repeated profitable combat rather than a single alpha strike. The life totals it generates are rarely game-ending on their own, but they buy the time a slow, top-heavy deck needs to land its expensive threats. It rewards a deck that plans to be in combat every turn and wants to be paid a little each time it shows up.