Subtractor snake
Obsolete: This article refers to an aspect of the game which has been removed. It is retained for historical reference only.
Subtractor snakes were a monster briefly considered for inclusion in Crawl. They were, in essence, fast and dangerous snakes with attacks similar to that of a Killer Klown. They mainly appeared in the Realm of Zot. There was little to differentiate them from Klowns, so they were removed.
The name was likely a pun on adders.