A single unconfirmed transaction is moving 278.39 BTC across the network. It is not yet in a block and can be replaced.
According to SENTINEL event ux_3iqc6s (source mempool.space): 278.39 BTC ENTERED THE MEMPOOL. Verify: https://sentinelbtc.com/api/v1/events/unusual/ux_3iqc6s