"When They Use These Spines, They Puncture Them Really Deeply Into Their Attacker. They Can Deliver Venom Into The Wound"

The name of these creatures immediately lets you know they’re not something to be messed with. Assassin caterpillars (Lonomia) are the larval stage of the giant silkworm moth and they are believed to be the deadliest caterpillars in the world.

Found in South America, these creepy crawlies protect themselves with a very special coat of armour: their bodies are covered with hollow, hair-like bristles called setae.

These are designed to break off, but they still do the job by delivering an unbearable sting. Think of it like their bodies are covered with hypodermic needles ready to stab you with some toxin if you brush past them (which is easily done as they camouflage so perfectly into tree bark).

The venom is stored in a sac at the base of each hollow bristle and when a bristle punctures the skin of a victim the venom flows through.

“If a person should inadvertently touch a group of these hairy cryptic larvae present on a tree trunk or branch, this can cause massive internal haemorrhaging, renal failure, haemolysis and even death (most frequently resulting from intra-cranial haemorrhaging),” says Guinness World Records on its website.

Researchers are intrigued by the properties of the venom that prevent blood from clotting and hope it might inspire new medical treatments.

This article by Melissa Hobson was first published by Discover Wildlife on 27 June 2026. Lead Image: Centro de Informações Toxicológicas de Santa Catarina, Public domain, via Wikimedia Commons.