Finster made this monster and it caught Kimberly's flu. He was destroyed by the Thunder Megazord.
"A Friend in Need, Part 2 & 3"
Vampirus hatched out of an egg that was place along with Tenga eggs. It made Ninjor angry was beaten by his Samuari form. He was destroyed by the Ninja Megafalconzord. He later appeared as a divide and conquer attack devised by Rita and Zedd.
"Ninja Quest Part 1, 2 & 4" & "A Different Shade of Pink, Part 1"
Artistmole was pulled out of Kimberly's nightmare where he represented her mother's fiancee. Then in the real world, he drained the color out of the rangers. Kimberly destroyed his palette and the colors returned. He was destroyed by the Ninja Megafalconzord. He made several cameos later.
"A Brush with Destiny" & "A Different Shade of Pink, Part 1"
Rita and Zedd made this monster out of an oriental latern that belonged to Billy's parent's friend Ko. He was destroyed by the Ninja Megazord and made a few cameos later on.
"Passing the Lantern"
Marvo the Meanie
Rito Rito planned to turn the Ninja Rangers into monsters, but since he had Zedd's staff pointed the wrong way, its energy turned Mr. Wilton, a teacher that switched places with Rocky, into a monster instead. Marvo turned all the rangers except Rocky into contaniers of liquid. Rocky had to turn the rangers back to normal before destroying Marvo because they would stay that way if he didn't. When Marvo was finished by Ape Ninjazord, he turned back to Mr. WIlton. The monster was resurrected, most likely without Mr. Wilton, as an audience member in the Machine Arena and made several other cameos.
"Wizard for a Day"
When Finster was making a mold for a centipede, a gootball was accidently mixed in and Centiback turned Rito, Rocky's friend Alan, his uncle Joe, Bulk and Skull and his ranger teammates into footballs. Ninjor and Rocky turned them back to normal and destroyed the monster with Ninja Megazord. He made a few cameos after that.
"Fourth Down and Long"
Face Stealer
Face Stealer was an ancient monster that was freed from a vase that was stolen from an museum. It stole Adam, Aisha, Bulk and Skull's faces. It was destroyed by the Ninja Ultrazord.
"Final Face-Off"
Hate Master
Created by Lord Zedd and Rita Replusa from Finster's evil seeds and he casted hate into the Rangers with dance and rap. Aisha was not effected because of a necklace her grandmother gave her. It was destroyed by an onslaught from the Ranger's zords. He made some cameos after that as well.
"Stop the Hate Master, Part 1 & 2"