As strange as it may seem... I actually WANT these things.
If anyone in the area of Athens, GA, USA has an infestation of Convolutriloba retrogemma, C. longifissura, or C. Hastifera, I will GLADLY come to your home/business (this includes pet stores) and siphon out as many as I physically can FOR FREE.
I am conducting research on the nature of the symbiosis between these worms and their algal endosymbionts and tend to run through populations rather quickly.
I am an experienced aquarist as well as a coral/invertebrate ecologist, so I fully understand the delicate nature of tank systems, i.e., you needn't worry about some hack coming in and flailing about willy-nilly in your aquarium.
Cheers,
Tom Shannon
Institute of Ecology
University of Georgia