Adders are a type of deadly snake seen in the original Jonny Quest series episode The Curse of Anubis. There were three of them.
All 3 were small, with an orange-brown color.
"The Curse of Anubis"Edit
In this episode, the adders were locked in a tomb in the remains of a lost city with Dr. Benton Quest and Race to make sure they didn't escape, and if they tried to, the adders were to kill them. These orders were given by Dr. Ahmed Kareem. When Jonny and Hadji found the two men, Hadji used music to serenade them and get them to peacefully leave. The adders weren't seen for the rest of the episode.