The blue sea slug is shown here out of water, and thus collapsed; these were found on a beach. Picking up the animal can result in a painful sting, with symptoms similar to those caused by the Portuguese man o' war.
^Piper, R. Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals. Greenwood Publishing Group. 2007: 42–43. ISBN 978-0-313-33922-6.
^Thompson, T. E.; McFarlane, I. D. Observations on a collection of Glaucus from the Gulf of Aden with a critical review of published records of Glaucidae (Gastropoda, Opisthobranchia). Proceedings of the Linnean Society of London. 2008, 178 (2): 107–123. doi:10.1111/j.1095-8312.1967.tb00967.x.
MILLER, M. C. Aeolid nudibranchs (Gastropoda: Opisthobranchia) of the family Glaucidae from New Zealand waters. Zoological Journal of the Linnean Society. January 1974, 54 (1): 31–61. doi:10.1111/j.1096-3642.1974.tb00792.x.