One user lost $1M USDC to MEV bot after mistaken transaction

One user made a mistaken transaction, sending $1 million USDC to a contract address. A MEV bot swooped in and took the funds before they could be locked. 

The Ethereum user made a common mistake – sending funds directly to a smart contract address. In this case, the wallet owner wanted to bridge $1 million, but did not follow the proper steps. Instead, the wallet holder sent the funds directly to the contract address. 

The transaction was recorded, and if filled, it would have frozen the funds forever, as if sending them to an invalid address. However, it was also noticed and swept by an MEV bot, which held the funds. 

Looks like some unlucky soul just sent $1m USDC to a bridge contract directly instead of calling the proper methods, getting it all immediately sweeped by a MEV bot 😭😭💀💀 pic.twitter.com/N7WGMSG4vS

— deebeez (@deeberiroz) September 16, 2025

The MEV bot was probably set out to watch for transactions to the contract, as it immediately noted the transfer. 

The initial owner who sent out $1 million received the funds from a large-scale wallet, possibly an exchange, then attempted to bridge the stablecoins. 

MEV bot stores the funds in a dedicated wallet

The destination MEV bot wallet just saw its biggest transaction for 1 million USDC. The funds are held in the wallet, which received its biggest single transaction so far. 

Previously, the bot swept smaller USDT and USDC transfers. At this point, it remains unknown if the MEV bot will be able to return the funds or if its purpose is to save lost tokens. 

On-chain analysts also noted the bot’s actions contained an exploit call to the bridge contract. The MEV bot sent a request to the bridge contract and got an approval to withdraw $1 million. 

its a "exploit", he sent his own address (7702 delegated to contract code), then the contract approved him infinity and he just withdrew it. pic.twitter.com/ffw8BKvg6K

— yannickcrypto (@YannickCrypto) September 16, 2025

The withdrawal, in fact, may still suggest the initial $1 million is stuck in the contract, while the bridge is now at a loss. The MEV bot paid 0.11 ETH for the immediate execution of the transaction. 

On Nansen, the recipient address is now tagged as ‘token billionaire’, a relatively new wallet starting its first transactions in June. Until the recent addition of $1 million USDC, the wallet had a smaller portfolio on multiple chains, including BNB Chain, Base, and Arbitrum.

Can the user regain the funds? 

The wallet used to sweep the USDC seems to be set to claim small sums sent by mistake. There are no signs of ethical MEV usage, which can return some transactions. 

For Ethereum users, block builders have become essential. Over 82% of traffic goes through MEV boost, generating over $1 million in daily fees. 

At this point, the wallet owner may only receive the funds if the MEV bot owner sends them willingly. The best approach is to manually check destination wallets and never send funds directly to a contract address.