EnVygle (en-voy-gul) is an illegal street drug. Also called, for short, "V-G".
EnVygle is a combination of a drop of vampire blood mixed with gargoyle blood.
V-G cures all injuries, reverses aging, increases strength, stamina, and sharpens senses.
V-G is severely intoxicating and incrementally addictive. Its effects wear off over time. The longer you continue to take it, the faster it wears off each time, and the more you require to gain the initial high and the improvements. Additionally, the damage is magnified each time it wears off in all instances except injury.
A person of 50 who takes it may be aged like a person of 51 once it wears off the first time. The next time, he will have aged as if he were now 53. Upon subsequent withdrawals, the increment increases; 56, 61, 70, 82, and so forth with increased aging. After 6 doses, a 50 year old man may appear to be 82, with many attendant age-related illnesses.
Thus the desperation to obtain more of it increases with each dosage. This secret has been well protected throughout history, for while its ability to cure life-threatening injury is significant, the resulting life may well not be worth living at all.