Donatello is the master of machines, and has an intellect beyond his limited teenage years. During battle, someone with that much brainpower is called upon to invent new ways to win, and Donnie has always risen to the occasion. In no series was this truer than the 1987 cartoon. Donatello was at the top of his game in creativity, for better or worse. His inventions surpassed anything a human scientist could dream up, and they (usually) proved effective, no matter how goofy they seemed. These are the best of the best and the oddest of the odd, and they showcase Donnie’s genius perfectly.

The Dream-O-Vision Helmet, on the other hand, is one of those inventions best left for the drawing board. This particular gadget was designed to project the imagination as a 3-D hologram. Unfortunately for the turtles, it worked a little too well. Michelangelo’s nightmares of a monster named Creepy Eddie caused a malfunction that brought the dream to life. Mikey and Leonardo get stuck in the dream world, while Raphael, Splinter, and Donatello are forced to fight Creepy Eddie in the real world. Fortunately, everything works out for the turtles in the end, but it just goes to show that not all of Donnie’s gizmos should be built.
The Personality Alternator might not be Donnie’s worst invention, but it certainly had some of the worst consequences. Designed as a way to get Leonardo to lighten up, the others zap him and he becomes a wisecracking jokester. Much to their dismay, this only makes the situation worse, and Leo stops fighting completely. Fortunately, a little coercing from Splinter gets Leonardo to shake off the effects on his own, but the device proved effective, and could have been used on others (like Raphael to make him less abrasive).
These were just some of the myriad inventions Donatello was able to concoct during that 10-year run on television. They weren’t all winners, but every single gadget came from a place of genuinely wanting to make life easier. From the practical to the absurd, Donnie certainly was a genius, even if what he created often led to more trouble than it was actually worth. In the end, his inventions will always live in infamy as one of the best aspects of the Teenage Mutant Ninja Turtles.