Unknown key format

What game?

Some old games had/have other size/length keys than 5-5-5.

And, I'm pretty sure if a dev wants to import keys, they can come in a different format.

Just look in the shop you bought the game.

The key was supposed to be Worms WMD activated on Steam but it doesn't match the key format there. I already refunded it but i'm just interested if it was just incorrect or for some other platform than steam.

There are other formats of steam keys. For example box copy of Prey from 2006 has a really weid steam key.

At least did you tried it on Steam? There are a few different formats that do work.

It may be for PlayStation or another console.

Some promo codes has to be used on special promo pages, and then you'll get the real code. Kind of hard to know where though for this one.

Perhaps it's a Desura key.