A word used to establish that the previous statement was false, usually followed by laughing. This is usually used when the user is unsure weather or not the joke was realised or wants to make it apparent that he or she was using sarcasm.
Besides it's actual meaning, there was an oldschool rapper named Syke. He was one of Tupac Shakur's greatest friends and appeared in serveral of his songs. He's most famous for singing in 2Pac's songs "Picture Me Rollin'" and "How Long Will They Mourn Me?"
A misspelling of the term "Psych". Most often used by people who have no idea what the term actually means, and only a loose grasp of what the appropriate context is to use the term. Also misspelled "Sike"
Brody: "Your mom blew me last night!! Syke!!"
James: "I'd have to believe it before you could actually Psych me out. I bet you'd spell it with an S too, wouldn't you?"
Brody: "Whatever, faggot. You SO believed it!!"
James: "Stop breathing my air."