MSM-04 Acguy is a fictional amphibious mobile suit from Kidou Senshi Gundam, used by the Principality of Zeon during the One Year War. Designed for underwater operations, it is recognizable for its rounded body, clawed arms, and stealth-focused profile. In the series, Acguy appears in special missions and reconnaissance or infiltration roles rather than frontline combat. It became one of the most memorable Zeon mobile suits due to its distinctive appearance and recurring use in Gundam media.