Lobopodians, a paraphyletic group of Palaeozoic vermiform animals bearing metameric appendages, are key to the origin of extant panarthropods. First discovered in 1983 on Mount Stephen (Yoho National Park, British Columbia), the Cambrian (Wuliuan) Burgess Shale lobopodian nicknamed “Collins’ monster” is formally described as Collinsovermis monstruosus gen. et sp. nov. A formal systematic revision of the poorly known lobopodian Acinocricus stichus from Utah is also provided. The body of Collinsovermis is plump and compact, lacking space between lobopod pairs but shows the diagnostic suspension-feeding characters of luolishaniid lobopodians. The six anterior lobopod pairs are elongate, adorned with long and slightly curved ventral spinules arranged in a chevron-like pattern. The eight posterior lobopod pairs, which attach to a truncated body termination, are stout and smooth, each terminated by a single strong recurved claw. Each somite bears a pair of dorsal spines; somites 4 and posteriad bear an additional median spine. The spines on somites 1–3 are much shorter than the spines on the remaining somites. The head is short, bears a pair of antenniform outgrowths, and is covered by an oblong sclerite. Collinsovermis plus Collinsium and Acinocricus comprise a sub-group of stout luolishaniid lobopodians with remarkably long spinules on the front lobopods, interpreted here as a clade (Teratopodidae). This clade is distinct from both the comparatively slenderer Luolishania and a sub-group composed of Facivermis and Ovatiovermis with posterior lobopods reduced or absent. Luolishaniids were mostly sessile forerunners of arthropods that had coupled efficient suspension-feeding devices and, as in Collinsovermis defensive features.

The phylogenetic analysis was primarily based on morphological observations of fossil specimens.