The cryptocurrency community was taken aback on Tuesday by the fact that someone paid a whopping 2,100 ETH ( worth $300,000) in transaction fee for a 0.1 ETH ( worth $14.4) transaction. The weird transaction was first spotted by China-based Cheetah Blockchain Security Center.

The transaction took place at 01:19:12 AM +UTC, Feb.19 at block height 7,238,290. Ethereum mining pool Sparkpool received the 2,100 ETH reward for mining one single block. The normal reward for mining one block is 3 ETH, 700 times less than what the mining pool got from this transaction.

Sparkpool published a statement today, confirming it has frozen 2,100 ETH.

“ The abnormal event triggers the internal emergency response. We temporarily freeze the transaction fee, and wait for the sender to discuss a solution with us. If the sender does not contact us for a long time, Sparkpool will distribute the fee to miners,” Sparkpool said.

What’s even more surprising is that the security center also found four other abnormal transactions were sent from the same Ethereum wallet address (0x587ecf600d304f831201c30ea0845118dd57516e) with hefty transaction fees (ranging from 210 ETH to 840 ETH) to send a small amount of ETH on the same day.

Although it remains unclear who owns the wallet in question, based on the preliminary analysis, Cheetah Blockchain Security Center suggested that an innocent Ethereum user incorrectly set the Gas Price to 0.1 ETH (instead of Gwei, Ethereum’s main currency unit), which brought the total transaction fee up to 2,100 ETH.

SlowMist, another Chinese security firm,thought the wallet was owned by a miner, and there were two possible behind these weird transactions. First, it could be caused by a programming bug; the other reason was a mining pool launched activities during the Lantern Festival to appreciate miners’ support.

Generally speaking, the higher the transaction fee is, the faster the transaction on the Ethereum blockchain will be proceeded. However, it makes no sense for anyone to pay astonishingly high transaction fees for a small amount of crypto.

As a matter of fact, 2,100 ETH is not the most expensive transaction fee spent for a crypto payment on the Ethereum network. On July 2, 2018, an user had to spend 5,862 Ether (worth around $2.7 million on that day) on Ethereum gas to send transactions due to the network congestion. It was the highest amount spent on Ethereum transaction fee in history.