Space Honey is an extremely potent sedative, with a little chant to help you remember just how potent:
One spoonful calms you down. Two spoonfuls help you sleep. But three spoonfuls and you’ll go into a sleep so deep you’ll never wake up. Never!
Fortunately, Space Honey is actually just a hallucination, caused by poisoning from space bee stings. Or else Leela would really have been in trouble.