Defeat the professor's radscorpion in three challenges

 is a quest in Fallout 2.

Quick walkthrough
You can only win the Intelligence test, a chess game, by learning the Flying Liver Attack from Seymour after doing him a favor. The other two test your Perception and Agility and can be won by stealing the radscorpion's Spectacles, or if this is not enough, dosing him with the two drugs Jet and Buffout.