G.U.A.R.D.O. was a robotic guardian built by Dr. Venture to provide security while Brock Samson was away. However, when Dr. Venture falls asleep before programming the family into G.U.A.R.D.O.'s friendly file, it attempts to destroy them. Fortunately for the Ventures, its attentions is eventually diverted to the henchmen of Baron Ünderbheit and The Monarch running wild on the compound and G.U.A.R.D.O. is able to satiate its appetite for destruction on the intruders until Brock runs it down with Adrian.