2.) Someone who spikes people's drinks at a party, I.E: Adding drugs/alcohol to them for fun or profit.
3.) Madman (my buddy, not the admin) on a really fucking bad day.
A.)Tom is such a spiker. We want him at the party?
B.)Only for the girlfolk.
A.)Holy shit, madman went spiker today.
b.)Oh shit, where do we hide now?
It's also been known as "spiking" and/or "getting spiked".
Guy 2: Yeah, someone gave him a Spiker and at The White Dove. He thought it was a Skunktail. Get this, he lost all his money, his ID, and most of his clothes.
Guy 1: Is he still shitting?
Guy 2: Hasn't stopped.