I guess I thought that the previous wording would remove the aura enchantment text but I guess that does need to be spelled out.

Yes, Auras who are somehow attached to something they couldn't enchant move into the graveyard. The Equipment type wouldn't change that. Simic Guildmage does something similar, it moves Auras to other permanents. Notably they need to be able to be enchanted by that Aura, otherwise the ability will have no effect. I'd also suggest making this card a permanent. Either it could be an Aura that targets other Auras, and it would say something like: enchanted Aura is an artifact equipment in addition to it's other types. : equip enchanted aura to a permanent this aura could enchant. Or if you want to be broader it could be a normal enchantment with: Auras you control are artifact equipments in addition to their other types. : equip target aura you control to a permanent it could enchant. I have no idea if the wording is correct. Also, this effect would come from this aura, not the individual auras. Also, also, I really liked the idea of your opponents setting the equip costs, but that isn't in my idea. I bet you could write it in a way that enables the individual Auras to have that effect instead of coming from this aura, but I bet it would be more difficult to write.

What zzo38 writes is mostly correct, though there are some details to consider. E. g. the equip ability won't have "no effect" on an Aura with e. g. "enchant artifact" - the equip ability will just only manage to move the Aura Equipment to a creature; then, unless it's an artifact creature, the Aura Equipment will become unattached and then be buried for being unattached.

There are a lot of ways this will work counterintuitively, so I suggest two big changes:

• Allow it to work only on Auras with "equip creature"; if you are really certain what you are doing, maybe a superset.
• Remove Aura and the enchant ability as you turn it into an Equipment - you might keep it an enchantment, but you really don't want to deal with the SBAs and rules around Auras.

As a further suggestion: How about rather than making it a sorcery that creates a counter as a marker, you turn this into an Aura itself?

I think that "enchanted creature" refers to whatever this permanent is attached to, so it would work, whether or not it is a Aura (although I think that it is still a Aura; it does say that it is still an enchantment, and rule 205.1a says that only "subtypes from the appropriate set" (artifact, in this case) are replaced; so, I think this means that if it is currently a Aura Food Curse, then it is no longer a Food, but is still a Aura Curse).

However, this gives that permanent equip, which can be useful whether or not it is a Aura, since it allows it to be attached to a different creature (although only a creature you control; it does not necessarily need to be currently attached to a creature you control) during a later turn. It also makes it a artifact, and also a Equipment, both of which might be meaningful in combination with some other cards.

Also, this effect allows use with any Aura even if it isn't one with "enchant creature". If it isn't something that includes creatures, then the equip ability won't work (you can still activate it, but it might not stay attached if it doesn't match), but it is still a artifact. If it is currently attached to something other than a creature, then the Aura dies (since, due to what I mentioned above, I think it means that it is still a Aura). If it says "enchant permanent", and it is currently attached to a creature, then being an Equipment as well as a Aura will prevent you from attaching it to a non-creature permanent.

I think this is interesting, but why would you want to turn an enchantment into an equipment? I like that the opponent gets to decide how high the equip cost will be, that’s very dynamic.

God that's some awkward wording.

I had the idea of a spell that turns an aura into an equipment. Sounds cool but how do you assign an equip cost to something which could be anything from Mechanized Production to On Serra's Wings to Eldrazi Conscription. So I thought I might give the opponent a chance to have a say in it, but I also don't want it to be zero if they're tapped out.

Does this even work? After all, aura's usually refer to "Enchanted creature" and equipment to "equipped creature". Neither of them say "attached creature" or "creature that this is attached to"

The design space is limited, you're right; I think it would have to be limted to a few legendaries (for important characters as above).

IMO, it's two creatures but it's a single permanent, so you can only tap or sacrifice it once as part of a cost.

Lyra Silvertongue/Pan VoR could be mono-U but you're right about the causing an issue for sure.

Effects that explicitly refer to cards after a single zone change can track those e. g. "When enchanted land dies, return that card to its owner’s hand." (Corrupted Zendikon).

More significantly: Eight-and-a-Half-Tails's second ability has he following ruling: "A permanent spell that becomes white this way will enter the battlefield and continue to be white until end of turn."

This doesn't actually work in the rules does it? The game cannot track what becomes of a spell once it resolves.