Bitcoin, Ethereum and a cluster of perpetual futures tied to artificial-intelligence and semiconductor stocks sold off sharply in a matter of minutes over the weekend, a synchronized flash crash that revived talk of a “Black Monday” ahead of the new trading week.

The damage was concentrated in leveraged positions. Perpetuals linked to AI and chip names fell hard before largely recovering: SOXL dropped 5.45%, SNDK lost 3.6% and MU slipped 3.42%. Most of those losses were erased within a short window, but millions of dollars of leveraged exposure had already been liquidated by the time prices bounced.

Crypto followed a similar script. Bitcoin slid by roughly $1,000 before rebounding about $1,200, while Ethereum fell from $2,420 to $2,360…