Venom (1981)

Kidnappers terrify... black mamba's kill!

When an international terrorist hatches a plot to kidnap a wealthy couple's child along with the family's maid and chauffeur, it seems like the perfect crime. Unfortunately, it goes terribly wrong when, during the kidnapping, the boy's pet Black Mamba snake is let loose. Vicious and deadly, the snake soon has everyone in the house captive and begins killing them off one by one.