The price of the second-largest cryptocurrency by market cap, Ethereum’s ether, has mysteriously flash crashed roughly 20% on Poloniex.

The crash occurred on the ETH/BTC trading pair and saw the cryptocurrency go from around 0.021 BTC to around 0.017 BTC, before quickly recovering. What’s behind the crash is currently unclear, although some suspect it could be related to a whale such as an ICO fund cashing out.

Ethereum price chartSource: CryptoCompare

Flash crashes are notably nothing new in the cryptocurrency space, and Ethereum’s ether is a particularly affected cryptocurrency. This partly because of how the token was distributed and how much wealth some ICOs managed to accumulate.

Back in 2017, the price of ETH flash crashed from around $300 to only $0.10 on Coinbase Pro, at the time known as GDAX, after the trading pair was hit with a “multimillion dollar market sell” order.

At the time the vice president of GDAX Adam White revealed on the exchange’s blog that the multimillion dollar sell order saw a number of orders get filled, from $317 to $224. This saw the price keep on dipping, triggering 800 stop loss orders and margin funding liquidations.

It’s possible something similar happened on Poloniex. The Circle-owned exchange hasn’t yet commented on the flash crash.