With merge split tokens, you can lock up any ERC20 and receive two proxy ERC20s in return: a PoS and a PoW flavor.
These proxy tokens are each redeemable in their respective forks-- the PoS token will be redeemable for the underlying on PoS Ethereum post-merge, and the PoW token will be redeemable on any PoW fork.
An example scenario: if Alice thinks $ABC will be worthless on the pow fork, she can mint some $ABC into $powABC and $posABC, and sell the $powABC on some market for more $posABC.
After the merge occurs, she'll be able to claim an underlying $ABC for each $posABC she has.
Inspired by this tweet from @inversebrah, I hope this small tool illustrates how to more efficiently discover the price of ETH and other tokens on the PoS vs PoW forks of Ethereum.
There are some additional details you can find in the repo's README. The code is unaudited and there's no canonical deployment, so please use carefully! 🐼🫡