describes a very haunting and/or traumatic situation in which the obsessed or deranged person pursues or follows a person with persistence. For example, the stalker would stand right behind you and breath on your neck. The stalker could also keep using instant messenger and always try to talk to you. The stalker also always comments on your blogs and you don't want them.
"Giant stalker just IMed me again. That's just stalkerrific."
adjective. A 'portmanteau' coinage, from Stalker + terrific. Something that is conducive to following someone surreptiously.
OMG! The new Facebook news feeds are like totally stalkerrific!