As one amused local put it: "I thought I was looking at a beach covered in used condoms."

Fair. But no. What you're actually seeing is Velella velella, commonly known as "by-the-wind sailors" — small, free-floating hydrozoans that drift across the ocean surface using a tiny sail-like fin. They're relatives of jellyfish but harmless to humans, and they periodically wash up on West Coast beaches in massive numbers when winds shift and push them shoreward. Reports from Southern California beaches popped up just days before SF's own blue invasion, suggesting a coastwide event driven by recent wind patterns.

This kind of mass stranding is entirely natural and, if you can get past the initial "what on earth" reaction, genuinely fascinating. Each Velella is essentially a tiny, self-contained sailing vessel — no engine, no subsidy, no SFMTA oversight required. Nature's most efficient transit system, arguably.

The creatures will dry out and decompose relatively quickly, so if you want to see them, head to Baker Beach sooner rather than later. They're not dangerous to touch, though the smell as they decompose isn't exactly pleasant. Think of it as San Francisco's version of cherry blossom season — fleeting, beautiful in its own weird way, and best experienced before it gets gross.

One thing worth noting for the uninitiated: Baker Beach's north end is clothing-optional, which prompted another local to report they were "rolling around on these naked" right now. To each their own. This is San Francisco, after all — the city where even the beach wildlife is delightfully strange.

Get out there and enjoy the free nature show while it lasts. No tax dollars required.