PONTV

Not to be too nerdy, but the females flip and swim upside down while they pound shallow sandy shorelines with pheromones to attract the males. This is probably one of the many evolutionary reasons they've got those dumb shells.

I'm no expert, but this is probably a spawning female that showed up too late to the party and got caught in a low tide.

That, or it was just dying.

Sometime evolution rewards ability to survive change.

Sometimes it rewards dumb luck.

Horseshoes crabs are clearly the latter.

@garcet Show them horseshoes some respect. We've used them for medicinal reasons for decades, but they've been working overtime in COVID vaccine safety checks.

Look up "horseshoe milking farms".