The Kid-C editor is a map editing utility used for modding Kid Chameleon, created by Van0014.
It was made to make map editing a little bit easier, by adding some convenience features.
The editor allows tile, enemy, block and platform editing. Though it won't show custom palettes.
Made with Game Maker 8, it pushes that engine beyond it's intended purpose.
More information can be found at the forum post of its original release, here.