One bid. One Punk. One trait.

The protocol stands at a single live bid. You can accept it for any Punk you own that carries an uncollected trait. The Punk enters a 72-hour return auction. If the market does not bid above the reserve, your Punk goes to the vault forever and the protocol makes permanent the rarest uncollected trait it carries. You don't choose that trait; the protocol derives it, the same way for every eligible Punk. How the trait is chosen.