(verb, transitive) To afflict oneself with a specifichallucination of a highly-anticipated occurrence, be it desired or not, due to hyper-vigilant watchfulness for said occurrence.
I hate watching meteor showers because I always imaginate more meteors than there really are.
Ever since I found that one Black Widow spider in my basement, I've been imaginating them in every corner of every room in my house!
Superfluous use of the word imagine, created out of necessity by the God, Rakim, to describe something beyond imagining (Also subsequently created to make a mad rhyme).
From the song : I Ain't No Joke "You like to exaggerate, dream and imaginate
Then change the rhyme around, that can aggravate me"