Stalker

The Stalker is a robot presumably built by Oliver Thompson and commissioned by Will Harangue in which he recorded Ben's aliens' moves in a video game motion capture-type scamming. It's first and only appearance so far, was in the episode Video Games. It recorded all but two of Ben's alien's moves, plus his own. Harangue spent approximately $36,000,000 to create the Stalker.

While the robot's AI was designed to trace and destroy Ben 10 and his car, it's automatic function is not very smart, as it once accidentally attacked a minivan that looked similar to Ben's car.

It was beaten when Humungousaur used a Sumo Slammer attack, which was not recorded into the database of The Stalker, causing it to go haywire. The defeat was followed by Nanomech which was able to go inside The Stalker and ruin the robot circuits in which caused it to malfunction and disable the robot. It was then crushed by Way Big with the remains crashing into, and destroying, Will Harangue's car.

Protection Against Ben's Attacks

 * Cannot be affected by Spidermonkey's webs
 * Fire extinguishers for Swampfire's fire blasts and a chemical liquid to kill his plants
 * Retractable mirrors to deflect Jetray's nueroshock blasts
 * Extreme durability against physical and energy attacks
 * Immense strength, allowing to easily overpower aliens like Humungousaur and Lodestar, as well as breaking Gwen's force fields
 * Multiple laser blasters
 * Cannon that can shoot strong adhesives to keep Cannonbolt in place
 * Can create enough heat to melt Big Chill's ice
 * Made of a material that can't be affected by Lodestar's magnetism
 * Retractable claw/tentacle
 * Electric antennae/tazers
 * Numerous missile launchers
 * Optional 360 degree vision
 * Can pinpoint the fighting style of Ben's aliens

Trivia

 * The Stalker does not have counter measures for Nanomech, Way Big, or Sumo Slammer attacks.
 * It seems to be a parody of the Omnidroid from The Incredibles.
 * The Stalker has Automatic and Manual controls.
 * The Stalker may be a parody of the Spider-Slayers from Spider-Man.