To ensure that Joe pays him back, Jasper chops off part of Joe’s finger to keep as collateral. However, lucky for Joe, Will coincidentally knows where he can find the exact amount of money Joe needs to complete the exchange. (Clearly, this seems more than a little fishy.)
Of course, Joe doesn’t find the money, he finds Will’s bipolar drugs instead, and Joe convinces Jasper to come by the house — with no intention of giving him the money he’s owed.
This, friends, is where Jasper makes his hasty exit from the series.