Shroid

Shroids are grey Shroob robots with yellow spots and green photoreceptors. They appear in the game Mario & Luigi: Partners in Time, and they are found in Toad Town. Shroid's name is a portmanteau of "Shroob" and "android".

In battle, Shroids use a variety of attacks to defeat its enemies. 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.

A Shroid can also summon a Shroob UFO to bring a spiked ball to the battlefield. This spiked ball either has a red "M" or a green "L" printed on it, indicating which Mario Bro. the weapon will be used against. The Shroob UFO drops the spiked ball on top of the Shroid. It then throws 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 then bounces back and hits the Shroid, causing it to malfunction if it still has HP left. 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, or vice versa).

The Shroid's last technique is less of an attack and more of a test of the Mario brothers' skill. It holds 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 repeats 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 throws both flags at the Mario Bros. The flag-throw cannot be dodged. If done correctly, the Shroid won't attack. Sometimes, the Shroid attempts to fake out the heroic brothers, causing the Mario Bros. to jump prematurely (and thus be damaged).

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.