A video game gave me this idea

[Cierfrost]

Universal Guardian

Fairy/LIGHT/Level 3/Effect

As long as this card is in your hand, deck or graveyard it is treated as though it were any non-specific named card. If this card is added to your hand or special summoned by an effect, this card must then be used as a material monster or cost. If you do not, end your turn. If this card is used as a material monster or cost, banish this card face down when it leaves the field.

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Hopefully it works as intended. I'm aware the wording is confuddly but its the idea that counts to me. 

[JessicaMuddy]

Do you mind giving us the ruling on these effects? Especially:

 

If this card is added to your hand or special summoned by an effect, this card must then be used as a material monster or cost. If this card is used as a material monster or cost, banish this card face down when it leaves the field.

I don't know what to make of this card yet.

[Cierfrost]

Basically if a card says "add/special summon/etc a CARDNAME monster/card", it is treated as that CARDNAME. It does not apply if it specifically asks for "Dark Magician", "Red-Eyes Black Dragon". But works if it asks for "a Dark Magician Card" or "a Red-Eyes Card", as an example that is.

 

If its added to your hand or special summoned, your next action must use it as a material monster or cost (Xyz Material, Synchro Material, Tribute Material, Tributing, Discarding, banishing etc), otherwise you cannot take another action besides ending your turn (added that in; sorry rushed the typing) and resume normal play during your next turn. 

 

The whole thing about banishing it facedown is just to remove it from play... permanently without any scuffling.