The name "Kill Bot" can identify a number of differnt varients of Robots in Futurama. They are used in war and for assassinations. Some have been created by Professor Farnsworth, Professor Wernstrom, and Mom.
The Octillion Killbots were an adversary faced by Zapp Brannigan, with a built in preset kill limit of 999,999.
After the kill limit is reached, they become peaceful.
Mom's Friendly Robot Co. Killbots
The most seen in the series are the Killbots produced by Moms Friendly Robot Co. These killbots are yellow and orange with two miniguns mounted on either side, moving on tank treads. They have been used to hunt Bender and Hermes across the country in "Lethal Inspection". They can be triggered to fire whenever a word relating to weapons is mentioned around them, i.e (Howitzer, Fire, Gun, Shoot, etc).
The Professor's and Wernstrom's Killbots
Professor Farnsworth and Professor Wernstrom have also made their own variations of Killbots, that show to be peaceful instead of violent. Wernstrom's Killbot is black with legs and two arms: one with a machinegun and the other with a sword.
The Professor's Killbot is also black with tank treads, a buzzsaw hand and a hammer hand, as well as a drill on its chest.
- Bender: Ah, shoot!
- Killbot: Someone said "shoot"! [It fires.]
- Killbot 1: Awww we're gonna get fired.
- Killbot 2: Someone said fire! [It fires.]
- Killbot 1: Cease fire. Mom called off the attack, although I don't see how it's her—
- Killbot 2: Someone said howitzer! [It fires.]
- "Space Pilot 3000" (1ACV01)  (mention)
- "Love's Labours Lost in Space" (1ACV04)  (deleted scene)
- "Mother's Day" (2ACV14) 
- "Crimes of the Hot" (4ACV08) 
- "Obsoletely Fabulous" (4ACV14) 
- Bender's Game 
- "Proposition Infinity" (6ACV04) 
- "Lethal Inspection" (6ACV06) 
- "The Mutants Are Revolting" (6ACV12)  (cameo)
- "Decision 3012" (7ACV03)