On March 8, 2016, there was a news post discussing multiple upcoming updates.  One such update was the Thwampus, which was the first time that it had ever been announced.
"Thwampus - That's right... The Wampus has a crazy cousin... He's even more elusive, and gets even crazier when you beat him!"There was a news post on August 17, 2016, in which a picture of the Thwampus was hidden. To this day, it is still possible to find the imgur link by going into inspect element. On June 12, 2018, WPS's team description was changed from "Be a Wampus!!" to "Be a Wampus!! or a Thwampus..." hinting at its upcoming release.