Summer of 80 or 81--just pre-dusk. Dark amber light with indistinct edges cruises due east over center of U campus. "Closes in on self"

Directly due east movement at 15-20 mph and a height of 3-5 stories. Object was distinctly seen from 2 blocks as it passed over 5-7 blocks of the campus (Quadrangle to "Red Square" to courtyard behind Student Union).  When the object was exactly due south of us,l it stopped as if aware it was being watched, paused for 2 seconds and then "closed in on itself."  What I mean by that is that the outer diameter of the object reduced within a second from the size of a Ford Pinto to zero, ie nothing, ie it no longer existed. ZERO sound.  Local FAA called & reported no radar objects.  Local weather station and University Meteroligical program called, & they both confirmed that NO experiments had been scheduled.