this is going to be hard to explain with no pics but on my monte i think its got something to do with the radio but its on my front window its like a thin plastic piece with to spiked ends about 8 in. long.the thing is its like 2 inches longer on one side than the other and it bugs the shyt out of me,is ther any way to allign it right or better yet relocate it out of sight.

 

i've never seen anything like that on the front window, they're not really supposed to put anything in your view on the windshield...but i'm not really sure what your talking about though

 

assuming you bought this car used, i would guess its an antenna for remote start/alarm. but yea, pics would help.