An “unlucky” maximum extractable value (MEV) bot took out a staggering $12 million flash loan but only made $20 from its exploits.

In a Sept. 5 X post , blockchain analytics platform Arkham Intelligence stated that the MEV bot took out a $11.97 million loan in Wrapped Ether (WETH) to “sandwich” a user trying to swap around $5,000 worth of Shuffle (SHFL) tokens. 

‘Unlucky’ MEV bot takes out huge $12M loan just to make $20 in profit image 0

Source: Arkham Intelligence

According to Arkham data, the MEV bot undertook a total of 14 transactions across the duration of its sandwich attack — lending, borrowing and returning around $700,000 in USD Coin ( USDC ) and WETH loans across decentralized finance protocols Aave and Uniswap.

However, after the MEV attack was over and gas fees were paid, the bot made just over $20 in profit. 

‘Unlucky’ MEV bot takes out huge $12M loan just to make $20 in profit image 1

The entire attack took place across 14 transactions. Source: Arkham Intelligence

According to data from Etherscan, the entire transaction was confirmed in a single block, meaning that the MEV bot executed all of the transactions within a span of around 12 seconds. 

How a sandwich attack works 

A sandwich attack occurs when an attacker “sandwiches” a victim’s transaction between their own two transactions to manipulate the price and profit from the user.

This is possible because the victim’s transaction is first sent to the mempool where it waits to be added to the next block. In the meantime, the attacker sets one transaction with a high gas fee — to ensure it is accepted first — and another transaction with a lower gas fee to ensure it is accepted after the victim’s transaction.

Related: Solana sandwich bot makes $30M from MEV arbitrage in 2 months

The attacker profits by buying the victim’s token at a price cheaper than market value and then sells it within the same block — taking in the difference between the revenue from the transaction minus the gas fees.

While this particular MEV bot failed to turn a profit, they have been highly profitable for their operators in the past.

In April 2023, the infamous MEV bot operator “ jaredfromsubway ” cashed in well over $1 million in a single week by executing a spate of sandwich attacks on buyers and sellers of the Pepe ( PEPE ) and Wojak (WOJAK) memecoins.

The bot’s name is a tongue-in-cheek nod to the popular sandwich chain Subway and its former spokesperson, Jared Fogle.

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