Answer to Parasite Case of the Week 527: Macracanthorhynchus sp., one of the acanthocephalans, or "thorny-headed worms."
Note its relatively large size, and the constrictions that give a false impression of segmentation. My techs call this a bubblegum appearance, which I think you can appreciate in this case:
HERE. It contains a lot of interesting information about the lifecycle, morphologic features and treatment of M. ingens (for example, human infection may be acquired by eating millipedes). Acanthocephalans are more closely related to rotifers than nematodes; hence Blaine's mention of rotifers in the comments.
Florida Fan seems to get a lot of these cases! HERE is one that he donated back in 2013 which nicely shows the eggs of Macracanthorhynchus. You can't tell M. hirudinaceus from M. ingens by its eggs, unfortunately. Take a look at the previous case for more information and a nice poem by Blaine.