TriScan

TriScan (トライスキャン) is a triangular program that appears in Cyber Peacock's stage in Mega Man X4. It will home towards X or Zero and deal contact damage. If it's not destroyed after a while, it will leave the screen.

TriScan Gold
TriScan Gold (トライスキャンゴールド) is a slightly modified TriScan that appears in the last Zero Space stage of Mega Man X5.

Other media
TriScans appear alongside Hover Gunners and Spike Marls in the Rockman X4 manga fighting Zero, but get destroyed by him.