Power Glove
The Power Glove is one of the many, many sucky accessories for the NES. First, there was the glove itself that was worn on the player's hand to play any NES game they wanted. Also, there were 3 sensors that was to be attached to the tv being played on. However, extremely long codes were needed to be inserted into the Power Glove to work.
While playing, the player had to move his or her hand around, but Nintendo knew it was going to suck, so they had a normal controller on the glove itself. Avoid this at all costs. It's sheer awfulness destroyed Syd Lexia's NES and shocked him for life.
What it looks like
The Wizard
In the film The Wizard, one of the characters uses the Power Glove to play a game. Why is this important? Because a now-famous phrase is uttered at that moment:
"I love the power glove, it's so bad."
Yes, it is so bad. So very, very, bad.