Craftable big nasty syringe.

[Captain_Bravo]

How about this: Make it craftable, but it can't be used on someone else. You can fill yourself with a shitload of chemicals instantly, but can't run around and stick someone with 120 units of Mercury after raiding Botany. Basically a giant, craftable, self-hypospray. Except since it's duct-taped together by stupid pubbies, it has a 5% chance of filling your veins with air and giving you an embolism.