Focused Infared Nuclear Detector Utilizes Hypersonics But Incredibly Looks Like Yoyo The F.I.N.D.U.H.B.I.L.L.Y. is a tracking device used by Numbuh 5 to find Billy Hocslawger in Operation: C.L.O.S.E.T. It is a version of the Y.O.Y.O., buffed up by Numbuh 2, since Billy was buried in his own clothes.