muggins
noun [ S ] UK humorous uk/ˈmʌɡ.ɪnz/ us/ˈmʌɡ.ɪnz/
傻瓜，易受骗者（常指自己）
a stupid person: often used to describe yourself when you have done something silly or when you feel you are being treated unfairly
I suppose muggins here will have to take care of the cat when they go on holiday (= I will have to do it but I don't want to). 我想只有像我这样的傻瓜才会在他们去度假时替他们照看猫。