A most incredible bastardization. A combination of the words "Oh My Fucking God", commonly used in internet slang as OMFG, and the title of the game "Phantasy Star Online", or PSO. Used in reference to Phantasy Star Online, or just to sound like a fucking idiot.
"d00d, si liek, PSOMFG, guY!1!!"
"Say that again, and I shall be forced to harm you."