Shroid

Shroids are grey Shroob robots with yellow spots and green photoreceptors in the game Mario & Luigi: Partners in Time. These powerful robots were stationed in Toad Town during the Shroobs' occupation of the Mushroom Kingdom. Shroids patrolled the ruins of the damaged capital city, attacking any intruders. The four Mario Bros. of past and present encountered many Shroids during the heroes' attempt to assemble the Cobalt Star and liberate Toad Town.

In battle, Shroids use a variety of attacks to defeat intruders. First, a Shroid can trap Mario and Luigi in crystals while charging up an energy blast in its arm cannon. The heroic brothers can break these crystal prisons by constantly jumping. After breaking the crystals, one of the brothers has to jump over the charged energy blast after the Shroid stops to fire. The brother it shoots at can be predetermined by looking at who it first traps in a crystal. However, if it is malfunctioning, it will shoot at the brother it traps second.

A Shroid can also summon a Shroob UFO to bring a spiked ball to the battlefield. This spiked ball will either have a red "M" or a green "L" printed on it, indicating which Mario Bro. the weapon would be used against. The Shroob UFO will drop the spiked ball on top of the Shroid. The robotic Shroob will then throw the spiked ball at the appropriate Mario Bro. This spiked ball can be deflected with a Hammer strike from one of the Baby Mario Bros. The weapon will then bounce back and hit the Shroid, damaging the robot in the process and causing it to malfunction. If the Shroid is damaged in this way, all future attacks will be reversed. (An attack that should normally hit Mario will hit Luigi instead, and vice versa.)

The Shroid's last technique is less of an attack and more of a test of the Mario brothers' skill. The robotic Shroob will hold up a series of flags: either a red flag, a green flag or both flags each time. Depending on what color the flag is, the corresponding Mario Bro. has to quickly jump (if the Shroid holds up both flags, both Mario Bros. have to immediately jump). The Shroid will repeat this process two to six times. If the Bros. mess up (either by missing a jump or by having the wrong Bro. jump), the Shroid will throw both flags at the Mario Bros., damaging them. The flag-throw is undodgeable. If done correctly, the Shroid won't attack. Sometimes, the Shroid will attempt to fake out the heroic brothers, causing the Mario Bros. to jump prematurely (and thus be damaged). Again, if the Shroid is malfunctioning, Luigi should jump if the Shroid holds up the red flag, and vice versa. Both brothers should still jump if the Shroid holds up both flags.

Another type of enemy, the Mecha-Chomp from Mario & Luigi: Superstar Saga, malfunctions in a way similar to a Shroid.

Trivia

 * In Mario & Luigi: Bowser's Inside Story, while Mario and Luigi battle the Shroobs, some Shroids can be seen frozen inside ice blocks.
 * Shroid's name is a portmanteau of "Shroob" and "android".