A ridiculous idea popped into my head: A scroll so evil, that failing not only had a chance to destroy the equipment being enhanced,
but others equipped or in the inventory as well! It would take multiple Shielding Wards in order to protect everything.

Now, a more sensible variation:
Imagine a scroll that cannot be used on a piece of equipment unless you have another of its kind in your inventory.
Upgrading a Stolen Fence would require another Stolen Fence; an Arcane Umbra Saber would require another Arcane Umbra Saber; et cetera.
(If a new UI element isn't added for choosing the equipment to sacrifice, it will pick the first one it finds in your inventory.)
It doesn't matter whether the sacrificed equipment is clean or has upgrades or stars, but it cannot be an Equipment Trace.
The scroll has a 50% success rate. If it fails, the upgraded equipment is destroyed at a 100% chance, but it can be saved by a Shielding Ward.
Whether the scroll passes or not, the sacrificed equipment is consumed, and it can not be saved by a Shielding Ward.
Upgrading an equipment fully with this scroll would require at least as many copies of it as the number of upgrade slots.

The scroll is probably split into general equipment types: one-handed weapons, two-handed weapons, armor, and accessories.
(Not pet equipment. Destruction and consumption of cash items would be too cruel, wouldn't it?)
Splitting among different level ranges is possible... but no, equipment type is enough.

I'm not posting this in the "Suggestions, Feedback, and Requests" because I don't actually want it to be implemented.

I'm just curious about people's opinion: Ignoring whatever the rarity and cost of the scroll itself might be,
what stats would this scroll have to give to be worth it?