Were you into crypto before the Ethereum merge? Now, you can prove it with a “Proof of Merge” NFT.

A pair of creative thinkers at Web3 firm Andreessen Horowitz have created a Proof of Merge NFT featuring metadata that dynamically evolves as the Ethereum merge unfolds.

A16z engineering partner Michael Blau and crypto investments partner Mason Hall engineered the black-and-white “Proof of Merge” Ethereum NFT, which goes through three phases triggered automatically by its smart contract. Software developer Zachm.eth designed the front end for the project.

The first phase of each Proof of Merge NFT displays before the merge and shows two separate circles. The second phase of the NFT, which occurred early Wednesday, shows two half-merged circles. The third phase will show the circles fully merged, forming a yin-and-yang symbol to indicate that the Ethereum merge is complete.


“It’s basically a side project that Mason and I hacked together really quickly over the weekend, this past weekend, and launched, and so far it’s been pretty crazy,” Blau told Decrypt in an interview.

The art is a nod to an Ethereum panda bear meme, said Hall, which shows Ethereum’s execution layer as a black bear and Ethereum’s consensus layer as a white bear. The two bears then combine to make the ultimate Ethereum panda bear, which has become a metaphor for post-merge Ethereum.

At time of publication, about 9,000 unique crypto wallet addresses have already minted a free “Proof of Merge” NFT, which are unlimited in number but can only be claimed before the merge is finalized. 


Why did they choose three phases? It was mostly for simplicity’s sake, says Blau.

“We’re actually storing each ASCII image on chain, and the more phases we wanted to store, that’s more data we have to store, which is more storage gas fees that we’d have to pay when actually deploying the smart contract initially,” Blau said.

Notably, Blau’s brother Justin Blau is also into crypto and wants to change the music industry through NFTs.

The NFTs—unique blockchain tokens which signify ownership—are non-transferable. If someone tries to transfer their Proof of Merge NFT, the transaction will fail, but the sender will still have to pay an Ethereum gas fee. 

This means that the Proof of Merge NFTs also function as a “proof of attendance” NFT of sorts, as they can only be held by wallets that minted them before the merge. The design features a similar black-and-white ASCII style to Blau’s previous Ethereum NFT collections, MEV Army and x0r, which both launched earlier this year.

The intermediate phase of two partially-converged circles was triggered by “a timestamp associated with the block,” Hall told Decrypt. “And so we use[d] a 12-hour window before the merge actually happens to represent this intermediate phase.”

The smart contract behind the Proof of Merge NFTs is also designed to be able to determine exactly when the merge occurs in order for the NFT to change into its third and final state—the yin yang symbol.

“The only way to detect if the merge happened on chain or not is to measure something called block.difficulty,” Hall said. “It’s an attribute of a block that returns normally how difficult it was to mine that block on the Ethereum proof of work chain.” 


This value will equal zero when the merge is complete. 

The Ethereum Merge will occur late Wednesday evening, according to estimates based on Ethereum’s current hashrate. The merge will fully transition the Ethereum blockchain’s mainnet from proof-of-work mining to a proof-of-stake system—a massive shift which is predicted to reduce Ethereum’s energy consumption by 99.95%.

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