Bowser is the main antagonist of Mario and Luigi's stupid and dumb adventures. He is notably more evil in this series. Whilst Bowser is a jerk in the main series, in this series he is nearly a sociopath. Bowser also takes the mantle as the secondary antagonist (only beaten by Principal Steinbeck) of the Bowser Junior's Summer School series, causing major problems such as raising the stakes with Chef Pee Pee's life if Bowser Junior were to fail his exam.