Klaustreich

A Klaustreich (KLOW-shtrykh; Grimm: KLOW-strysh; Germ. klauen "steal" + Streich "prank/trick") is an alley cat-like Wesen. They are typically known for being jerks in the Wesen community. Women often find male Klaustreichs irresistible, but it never ends well for those who fall for them as male Klaustreichs are very possessive. Monroe told Nick that it is a good idea to sleep with one eye open when there's a Klaustreich around.

Excerpt from Nick's diary
The Klaustreich I came in contact with was aggressive, predatory, sadistic, and treacherous.