The Shockwave is a weapon used by Shredder and Krang in the episode 1987-1996 animated TV series. It appears in the episode Wrath of the Rat King. According to General Traag, it was what allowed Krang to rise to power in Dimension X in the first place, and a symbol of his power.
When deprived of the Technodrome, Krang grew desperate enough to demand that his followers send it to him on Earth. However, gravitational disruptions caused it to land in the wrong place and be found by the police, forcing Krang to rely on the Rat King to help him recover the device. However, the Rat King took the Shockwave for himself instead, and it was destroyed in the battle with the Ninja Turtles shortly after.