Someone who pounces onto a conversation, relating what you are talking about to something no one cares about...usually something about themselves!
Guy:Hey, there is a new bar in Dinky Town called "The Library". It's introducing "super thirsty thursdays"
Narcissistic Gal:OMG, OMG, that bar is Awesome. It has maroon carpets...same color my bridesmaids will wear when Mark and I get married!
Guy: Ohh c'mon, we're talking important things here. Don't be such a Narcissistic Pouncer!