Zoostuck 2

beat him to death with your shoe

That might work, but it would be highly unprofessional. He may have thwarted your ingenious plans for the future of existence and might now be stealing those plans that are rightfully yours, but he's still a customer.

Plus, you might ruin a perfectly good shoe! It's just not worth the risk.

Put broken glass in your omelet.

On the other hand, serving him an incredibly dangerous omelet would be entirely professional, given how dangerous these omelets are already. That might just do the trick. However, as a matter of pride - you are, after all, the greatest omelet chef in Paradox Space - the omelet still has to be delicious.

So what will you put in this omelet to make it even more dangerous than it already is while improving the flavor?