Snakelike! Sometimes, specifically, of or related to the snake subfamily Colubrinae, which includes king snakes and rat snakes, or even just the genus Coluber. Sometimes, more generally and metaphorically, meaning cunning or crafty -- though this is a literary and almost obsolete sense, and is odd given most of the colubrine snakes are entirely harmless, unless you happen to stumble upon a cobra. Adopted around 1520 from Latin colubrīnus, from coluber, snake + an adjectival ending.
It is immune to viper poison but it is not immune to colubrine poison.