Angel's Tomb

The clever trick here is what it declines to be. As an inert artifact for most of any turn, it slips under sorcery-speed creature removal entirely: there is nothing to point a kill spell at until you choose to wake it, and that wake-up happens on your terms, in response to one of your own creatures entering. That selective vulnerability is the whole pitch. It animates only into a fragile 3/3 flyer that combat or burn answers cleanly, so the resilience is conditional on staying asleep, and an opponent holding instant-speed removal can still catch it the moment it stands up. The cost of that protection is steep on a stalled board: with no creatures of yours entering, it stays dormant and never becomes a clock at all. And even when it does wake, the animation is redundant once it is already awake for the turn: extra entries after the first do not stack into a bigger threat or more attackers. That mismatch (it wants a steady flow of your own creatures but cashes each turn out as a single evasive body) files it down to a slow role-player rather than a threat in its own right. It belongs in decks already generating creatures for other reasons, where the recurring flyer rides along tax-free on a board they were building anyway, and where its long stretches of dormancy double as insurance against the removal that would punish a real permanent.