acanthocephalan: any of various worms living parasitically in intestines of vertebrates having a retractile proboscis covered with many hooked spines
worm: any of numerous relatively small elongated soft-bodied animals especially of the phyla Annelida and Chaetognatha and Nematoda and Nemertea and Platyhelminthes; also many insect larvae
darkling beetle: sluggish hard-bodied black terrestrial weevil whose larvae feed on e.g. decaying plant material or grain