I think it need a smidge more edge. 'Slice you like shitake' or just 'slice you, shitake'. The threat just falls a little flat. It's still funny, but I can't help but think a little extra would go well.
I'll think about it... the problem is it IS good and well I might want to use it for later. I don't want the "snot" joke to be overpowered by something else.