This mug is perfect for many reasons.
1) No one will drink out of it. Because it's marked "poison".
2) Whenever you have a meeting with someone you hate you can smile at them while drinking it, thinking "I'd rather poison myself than sit here with you." It will make them very unsettled and the meeting will end early.
3) If someone goes to HR to complain you can just say that you're a big fan of the 90's band "Poison" and you don't like what they're implying.
4) You can use it to store your poison in.