The rules

1. Burn four, keep one.

   Pick the one you keep, then four to burn. The four are gone for good, and the one you kept is drawn again in the FlipFlopChart look, the same face.

2. The upgraded one is the pass.

   Whoever holds it gets into flipflopch.art. Sell it, and the pass goes with it.

3. One-of-ones are safe.

   The altar won't burn a one-of-one and won't upgrade one. A pass can't be burnt here either.

4. Only your own.

   All five must be in your wallet. Burning needs your permission for the altar first, and only you can use it: the altar checks that every token is the caller's. You can take it back below.

5. It can't be undone.

   A burnt token is gone from the chain. Nobody can bring it back, us included.

Check it yourself

The altar's code is public: KarmaAltar on Etherscan. Nobody can upgrade a token without burning four, us included.