A Seeker is an automated machine that is used principally for detection of hostile targets. It has otherwise been referred to as a "self-propelled surveillance device".[excerpt 1]
The Host/Hive Capture Force used a model of "Seeker" that operated alongside their Hunter IIs. Whenever they would detect movement from a hostile, they would alert nearby Hunters with a sound the B.O.W.s were trained to respond to.
Third Organization (2004)
Two variants of Seeker ("Flight-type" (シーカー飛行タイプ,hikō taipu?) and "Bomb-type" (シーカー爆弾タイプ,bakudan taipu?)) were also used by Jack Krauser during his fight with Leon S. Kennedy in the ruins on the island. The "Flight-type" utilized a machine gun on its underbelly and, as the name suggests, was able to fly, while the "Bomb-type" resembled a walking spider and, as suggested by its name, was strapped with TNT primed to detonate when finding a target.
↑Excerpt from CODE: Veronica webpage: Shūhen kiki no `jisōshiki kanshi-ki' ni yori kōdō no seigyo ga kanōna bun, heiki to shite no jitsuyō-sei wa orijinaru no hantā yori takaku natte iru. (周辺機器の「自走式監視機」により行動の制御が可能なぶん、兵器としての実用性はオリジナルのハンターより高くなっている。?)