Someone who far too regularly tags photos on Facebook at every possible occasion. These photos are usually unwanted.
Izzie: Hey Phil and Dan, that girl Holly Rodrigues has tagged another Facebook photo of you.
Phil: For fucks sakeRodrigues...
Dan: That girl is such a fucking Tagasaurus Rex!
Theasaurus was not a true dinosaur. It lived long after most dinosaurs and fed on the spare time of the verbose. But mostly, it had trouble spelling and pronouncing the word "thesaurus".
A Theasaurus can still help you find a synonym for "dapper" if you ask it nicely.