What causes wolf worms?

There is no such thing as a "wolf worm". It's possible you may have heard this term in a fictional context, like a story or game.

If you are thinking of a specific creature or parasitic worm, please provide more details about what you have in mind, including any other information you have about it, like its appearance, where it's found, or any other characteristics. This will help me understand what you are asking about and provide you with a helpful answer.