Most bike signs beside roads and trails are pretty cut-and-dry: When you see an outline of a bike, you know you’re likely welcome to ride there. But every once in a while we encounter something completely inscrutable that makes us laugh, or otherwise adds a little confusion and excitement to the world of cautionary traffic symbols.

bike warning sign

Where it is: Portland

What it looks like it means: Something—quicksand? A giant Lego?—is about to eat your front wheel so prepare to crawl to safety.

What it means: Hit the train tracks as close as you can to a 90-degree angle, or your wheel might get stuck—launching you over the handlebars.

slippery bike sign

Where it is: Everywhere

What it looks like it means: Snakes! Snakes are coming after your tires!

What it means: Ride with caution—road surface could be slippery or otherwise dangerous.

bike warning sign

Where it is: Unknown

What it looks like it means: Lock your bike, or Superman might steal it.

What it means: Please don’t do this? (But if you need to, make sure you film it like this guy.)

bike warning sign

Where it is: San Francisco

What it looks like it means: Tuck low in the aero position and prepare to meet your clone in a space-time implosion at this intersection.

What it means: Drivers, be alert to potential collisions: Cyclists are crossing from both sides ahead. (This one is less confusing when you realize it’s aimed at warning drivers and not cyclists.)

Where it is: Boston

What it looks like it means: There’s a disjointed hospital ahead? You’re about to enter a Frogger-like crossing situation? Prepare to limbo under this upcoming chain? We had so many theories.

What it means: Bikes, cross here ahead.

bike sign

Where it is: Japan

What it looks like it means: That idea you just had to sneak up on an unsuspecting pedestrian and ram him or her from behind? It’s funny. Go with it.

What it means: Dismount your bike and walk.

bike sign

Where it is: Switzerland

What it looks like it means: Bikes everywhere—backpacking, poppin’ wheelies, coming from all sides, riding in every direction. Chaos!

What it means: You’re at an intersection of bike paths. Go any direction you want!