Schlecht is a "bad," created from a misspelling of the word "bag" in the story "No Way Back." He looks like a black, fluffy ball of evil with a snakelike tongue and an abrasive personality. He still possesses bag-like qualities, such as an opening on his head that things can be stored in. Jay and Rhus Radicans named him for the German word for "bad." Presumably, he lived in Jay's response center until she retired. His current whereabouts are unknown.
Ironically, "Schlecht" was misspelled as "Schlect" in the original version of "No Way Back." There is no indication in the mission that this was a deliberate attempt at irony, though, so it was corrected in the version archived at PPC: The Lost Tales.