Janis thorn
From Tardis Wiki, the free Doctor Who reference
Kanis thorns are small, poisonous thorns used by the Sevateem as weaponry. Janis thorns are thin thorns about the length of a finger, with a poison coated tip. This poison causes first paralysis and then death in Humans.
Though there is no naturally occurring cure in nature, an anti-toxin was created by the Doctor using a bioanalyzer. (DW: The Face of Evil)