Pristine Angel

Conditional protection is the rarest kind in Magic, and this is its defining experiment. Most protection is static: a creature either has it or it doesn't. Here the safety net is bolted to a single state, untapped, and the whole creature is engineered to keep itself in that state. The spell-cast trigger is the engine: every time you cast anything, you may straighten it back up, restoring protection from artifacts and from each color in time to block, to swing again next turn, to dodge a removal spell aimed during your own activity. The window where it is vulnerable is precisely the window after it attacks, before you untap it. That tension, that the card is a fortress only when it isn't doing anything but exists to do things, is what makes it more than a six-mana 4/4 flier. The protection clause is sweeping enough to make it nearly unkillable by spells and unblockable by colored creatures, but it cuts both ways: protection from each color means your own auras and combat tricks slide off it too, so the card asks to be supported by colorless artifacts and untap triggers rather than buffed directly. It reads as a deliberate answer to a metal-heavy era, a white blocker that walks through the very artifacts and colored threats it was built to outlast.