Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Lāŏcŏon (Laucŏon), ontis, m., = Λαοκόων, a son of Priam and Hecaba, priest of the Thymbrean Apollo, who was killed, with his two sons, at the altar by two serpents, Verg. A. 2, 41; 201; Hyg. Fab. 135: sicut in Laocoonte, in the statue of Laocoon, Plin. 36, 5, 4, § 37.
Form Laucoön, Petr. 89.