Baler twine is amazingly tough, although it would eventually fray where it rubs against the wooden guides. Braiding it made it slightly less prone to fraying. I computed the marble muzzle velocity at 150 miles per hour by shooting a marble into a ball of plasticine, and measuring how high this ball of plasticine was thrown. Although designed for marbles, this thing also shoots anything with the same cross sections. AA batteries work particularly well, although they don't travel nearly as fast as the marbles.
Some pens also work.
Growing up in the country, wasps nests and the possibility of getting stung were a frequent nuisance. In the summer of 1996, opportunity presented itself. Near a picnic table where some of us at work were always having lunch, there was a wasp nest in a crevice in the building. Wasps were frequently bothering us, but we could not even see the nest, just a gap in the concrete that they used for their entrance. I happened to have this incredibly powerful blower that I bought at a surplus store but never found the right use for.