At Europe’s largest invite-only tech startup conference on Tuesday, entrepreneurs have to walk the plank. Every startup founder that wants to pitch an idea at Pirate Summit has to uphold a time-honored tradition — balancing on a narrow piece of wood in front of investors. If they’re successful, their startup business could find some much needed financial backing to get it afloat.

Tech CEOs have three minutes to pitch their ideas, swaying slightly on the plank and resisting the temptation to stage dive into the crowd. In that time, they’re forced to put forward a clear, credible business idea. Some of the ideas are polished, conventional ways to get ahead, but others come out of nowhere — and things can get pretty weird. Here are four of the strangest ideas plank-walkers came up with at Pirate Summit.

Tinder for Fish (Fishpointer)

Fishpointer’s community is dedicated to finding the best fish in your local area. Unlike Facebook groups, where data is often outdated and hard to locate on a map, Fishpointer’s easy-to-use interface can help you find what you need. Unfortunately, global readers who want to get their fish on will have to wait: the startup is only targeting Romanian fishers for now.

eBay Meets Warcraft (Bidi)

Bidi is the addictive online game that everyone’s been waiting for. It’s an e-commerce platform, founded in Macedonia in February, with a tempting proposition: everyone pays one dollar for anything listed. This includes iPhones, MacBooks, high-end Canon cameras, and more. Everyone that enters competes in a giant multiplayer game, clicking rapidly for one minute. The last person to win gets the item for basically nothing, while the seller collects the proceeds and earns the item’s value back.

Duolingo for Toothbrushes (Playbrush)

Playbrush wants to make brushing your teeth fun and educational. The device attaches to the base of the brush, connecting via Bluetooth to a smartphone. There are a variety of minigames to choose from, but unfortunately, it doesn’t look like Halo or Call of Duty will be making an appearance anytime soon. The app’s more aimed at teaching children to brush their teeth, but hey, one can dream, right?

Graffiti Meets Printers (Sprayprinter)

Want to vandalize a nearby house but don’t have any artistic talent? Never fear, SprayPrinter is here! Simply chose a design from the app, connect up to a smart aerosol can and start spraying. The company is more focused on home decoration and the like, so it’s unlikely to condone using the app to become the next Banksy, but if you’re really desperate to leave your mark on next door’s wall, it’s nice to know there’s a glimmer of hope.

Photos via Mike Brown/Inverse

Mike Brown is a London-based writer with a passion for tech, politics, and photography. After studying Journalism at Columbia University in New York, he returned to the UK to cover the news as it happens around Europe. His work has been featured in IBTimes, Neowin, Building Magazine, and more.