In slang, a Mickey Finn (or simply a Mickey) is a drink laced with an incapacitating agent, particularly chloral hydrate, given to someone without their knowledge with the intent to incapacitate them or "knock them out"; hence the colloquial name knockout drops. Serving someone a "Mickey" is most commonly referred to as "slipping someone a mickey".[1]
The "spiking" of drinks is a practice used by sexual predators at drinking establishments who lace alcoholic drinks with sedative drugs.[2][3]