A plant of the genus Bidens (family Asteraceae), especially B. frondosa, having dry, barbed fruits with sharp pappi at one end which easily adhere to fur, clothing, etc.

(In full "sticktight flea") a flea, Echidnophaga gallinacea (family Pulicidae), which when feeding attaches itself firmly to a host by burrowing its head deep below the skin, typically remaining in place for a prolonged period of time; also called hen flea.