On March 5, Polkadot (DOT) experienced a flash crash at Binance perpetual futures which resulted in the contract trading as low at $0.20. While this could have been an honest fat-finger trading mistake, a number of indicators point to a planned-attack.
While no hard evidence will likely ever emerge, the open interest increase just 24 hours ahead of the event indicates that an attacker could have generated a $8.3 million profit by manipulating Binance's matching engine.