Aegis Angel

The wrinkle is what the indestructible clause protects: not itself, but another permanent, and only for as long as you control the Angel. That tethers the bestowed shield to a 5/5 flier's mortality. Point it at a combo piece, a manland, or your other threat, and you have built a fortress that collapses the moment someone deals with the Angel. The clean line of attack, then, is to kill the Angel rather than the thing it guards, which inverts the usual removal-priority calculus: opponents answer the body, not the protected permanent, and once the Angel is gone the grant evaporates on its own. Critically, the Angel itself gains nothing; it dies to any ordinary destroy effect, which is precisely the soft underbelly of the arrangement: the guardian is the most attractive target on the board, and it has no protection of its own. The "another target permanent" wording is deliberately broad, covering lands, enchantments, planeswalkers, and creatures alike, which is more generosity than the rate suggests. As a fair beater the six-mana 5/5 flier is unremarkable for its slot; the enters trigger is what justifies the card, a one-shot grant that rewards already having something worth protecting on the table when it lands. It is designed less as a finisher than as a bodyguard: a flier that makes one of your other permanents temporarily immune to the most common form of interaction, while remaining fully vulnerable to that same interaction itself.