Liquidity sweep / stop hunt
Price reaching into an area with obvious stop clusters (equal highs/lows, behind a level), triggering the orders, and then reversing.
For large orders to be filled, counterparty liquidity is needed; stop clusters provide that liquidity. Equal highs and lows are the most visible targets.
Practical takeaway: don't put your stop "where everyone puts it", and consider using the sweep of obvious levels as an entry trigger.