Last time I did that was attempting to cross what looked to be a wide shallow stream riding along the Mississippi river bank. It was 5' deep and quite swift then suddenly very shallow. Said drop off coming 8'-10' in perfectly as momentum faded and I leaned forward to fight the rest of the way across. I gurgled the strangest squeal of horror a human can make under water which turned into a whoop when I realized the bike wasn't going to get washed downstream never to be seen again.

3 hours of 75 rpm slow and low base work in fairly gusty winds. Holding form going that slow with no recent muscle memory was mentally taxing. Physically too based on how ravenous I was when I walked in the door.