Charybdotoxin (ChTX) is a 37 amino acid neurotoxin from the venom of the scorpion Leiurus quinquestriatus hebraeus (deathstalker) that blocks calcium-activated potassium channels. This blockade causes hyperexcitability of the nervous system. It is a close homologue of agitoxin and both toxins come from Leiurus quinquestriatus hebraeus. It is named after Charybdis, a sea monster from Greek myth.

The deathstalker is a species of scorpion, a member of the family Buthidae. It is also known as the Palestine yellow scorpion, Omdurman scorpion, and Naqab desert scorpion, as well as by many other colloquial names, which generally originate from the commercial captive trade of the animal. To eliminate confusion, especially important with potentially dangerous species, the scientific name is normally used to refer to them. The name Leiurus quinquestriatus roughly translates into English as "five-striped smooth-tail". In 2014, the subspecies L. q. hebraeus was separated from it and elevated to its own species Leiurus hebraeus. Other species of the genus Leiurus are also often referred to as "deathstalkers". Leiurus quinquestriatus is yellow, and 30–77 millimetres (1.2–3.0 in) long, with an average of 58 mm (2.3 in).