Think of ETH fees as more or less an auction. When you submit a transaction to the Ethereum network, you're hoping it will be mined as soon as possible. Miner

Think of ETH fees as more or less an auction. When you submit a transaction to the Ethereum network, you're hoping it will be mined as soon as possible. Miners select which transactions to include based on the miner fee. The minimum miner fee that is required for a transaction to be processed promptly is therefore constantly an open question / constantly changing, which gives rise to services like https://ethgasstation.info/ https://ethgasstation.info/ which attempt to tell you how much you should reasonably expect to pay. In terms of how today's outcome is possible: when you are submitting a transaction, any amount of ETH that you have on your account could validly be spent as the fee. So in this case, either by human error or a software bug, someone with a large amount of ETH in their balance essentially spent all of it on the transaction fee. The miner _gets_ all of those ETH. So some lucky miner just got a huge spike in profit.