Shielded by Faith
Most indestructibility Auras are static: they pick a host and stay put until something peels them off. The third line is what turns this from a protection spell into an engine. Because the Aura offers to relocate onto each fresh creature that hits the battlefield, it never wants for a body: as the board refills, the shield migrates to whatever entered most recently rather than sitting stranded on a corpse-in-waiting. Token generators make it a perpetual reattachment loop, since every new creature is another candidate to wear it, and the old host simply loses indestructible without the Aura tumbling into the graveyard. The trigger is a "may," so it never forces an awkward migration you did not want, and it reads "a creature enters" with no controller clause, so an opponent's fresh creature is a legal destination too. The clean combo turns that reattachment on its head: Siona, Captain of the Pyleas mints a token whenever an Aura becomes attached to a creature, and this Aura offers to attach whenever a creature enters, so Siona's token triggers the attach, the attach triggers another token, and the loop runs as long as you let it. The granted indestructible itself is unremarkable; everything the card is worth lives in the migration clause, which converts a one-target buff into a roaming insurance policy that follows the newest creature down and, paired with the right enters-the-battlefield payoff, stops following physics.
