Mmmm smells good! Just a sip…
1d8
1- A potent shrinking potion. You are now swimming in the cup alongside a drenched wizard.
2- Hot Green Slime. That’s what you get for mooching. Take 1d4 acid damage and roll initiative against a 1HD green slime.
3- Vampire Blood. Just kidding! Tomato juice!
4- Potion of Charm. Fall in charm with a random companion. No save.
5- Dragon’s Urine. You may spit fire ten feet for 1d10 fire damage as bonus action (or once/round). Lasts two game hours. Don’t ask what happens later.
6- Tomato Juice. Fooled you! Vampire blood! If you die in the next 24 hours you rise as a vampire spawn. Where is your master?
7- Tiny Water Elemental. You will feel dizzy and out of sorts until it passes in 5 hours. Disadvantrage (or other penalty) to constitution saves.
8- Damn Good Coffee! You are buzzed and have advantage (or other bonus) on all initiative rolls for the next 3 game hours. After that, you crash and have disadvantage (or other penalty) on initiative rolls after that until a long rest or more Damn Good Coffee!