Scatterbrain

Scatterbrain is a monster from Mighty Morphin' Power Rangers Season 2 and appears as the main antagonist in the episode "When is a Ranger Not a Ranger?".

Scatterbrain was created by Lord Zedd from a kaleidoscope that new Black Ranger Adam owned and had the ability to erase people's memories. Immediately after being created, he wiped Kimberly, Billy, and Tommy's memories cleans. When Rocky, Adam, and Aisha, who are all new to the team are informed by Zordon on what happened, they take the three back to the Command Center and devise a plan reverse the effect. Rocky and Aisha take Kimberly and Tommy to the desert to lure Scatterbrain outside of the city so as to keep innocent people out of harm's way while Adam goes to Billy's lab to fetch prisms. Adam and Billy arrive as Aisha and Rocky are morphed and fighting the monster. Just then, Scatterbrain uses his beam on Adam, erasing his memory and taking Billy's again as well, leaving Aisha and Rocky to face the monster on their own. They try to secure the prisms, but they too fall victim to Scatterbrain's beam and lose their memories and are demorphed.

The prisms fall to the ground next to Bulk and Skull, who had been watching the fight and had finally discovered the Power Rangers' identities. With the Rangers now completely amnesiac and helpless, Scatterbrain celebrates his victory. Just then, Bulk and Skull confront Scatterbrain and challenge him to a Wild West-styled showdown, complete with a randomly-drifting tumbleweed. Scatterbrain threatens to destroy their minds as well, but they stand their ground. What Scatterbrain doesn't realize is that they picked up the prisms and are hiding them behind their backs. After a tense standoff, Scatterbrain fires his beam and scatters what few brains Bulk and Skull have, but the beam also hits the prisms and bounces it back to the Rangers, restoring their memories and morphing them. With their memories restored, the Rangers thank Bulk and Skull for saving them. The two are mostly fine, but have also lost their memories of the Rangers' identities and the fact that they saved them. When Lord Zedd, discovers that his plan was ruined by a couple of meatheads and not the Rangers, he makes Scatterbrain giant-sized with a growth bomb and the monster fights the Thunder Megazord before being destroyed by its Thunder Saber.

Trivia
Scatterbrain is notable in being one of the few villains or monsters who actually managed to defeat the Power Rangers, only to be thwarted by outside interference, in this case, Bulk and Skull.