The RX-78GP02 or Gundam "Physalis" is one of the new Gundams that are made after the One Year War. It was Gundam jacked by Anavel Gato AKA "The Nightmare of Solomon" on September 0083. And thus, GP02 is a ZEON Mobile suit. The 2nd Gundam MS that can used on the side of the Principality of Zeon.
Unlike the one seen in the OVA 0083, the Gundam Physalis utilizes a Beam Bazooka instead of it's atomic warhead Bazooka. The Beam Bazooka was a new weapon developed by the Delaz Fleet of Zeon remnants that was meant to replace the Physalis's Atomic Bazooka as its main armament after it fired the nuclear warhead during Operation Stardust. However, before Gato could use it, Both the GP02A Physalis and GP01FB Zephyranthes Full Vernian were destroyed in a one-on-one duel, which occurred almost immediately after the Physalis delivered its atomic payload at The Federation's scheduled naval review at Konpeito (Formerly the Zeon asteroid base Solomon). Out of universe though, the Beam Bazooka was designed for the "Harmony of Gundam" line of original designs, and supposedly made specifically for the Physalis to use in video games, as the Atomic Bazooka would normally be far too troublesome and impractical to implement and use in many ways.
The Physalis has the highest hit point in both its body and its shield. While the GP01 Gundam "Zephyranthes" emphasis on speed and manuevarability, the Physalis is about overwhelming power.