An immortal creature that cannot be destroyed with human weaponry.
It's also known as "Sora".
An interesting glitch appears in R-Type Dimensions, using the Infinity mode. During the battle against the Bydo (Core), Wins, after flying their pattern, will eventually stop flying their pattern and latch onto the pilot's ship, destroying it. When the new ship spawns, the Wins will latch onto that one and destroy it as soon as the invincibility ends, a pattern that continues until the Bydo Core has been destroyed. Normally, after flying a pattern, the Win is supposed to attack directly and destroy the pilot, who then must restart from the last checkpoint and approach the Core again. Since the battle against the Core doesn't "restart" upon pilot respawn during Infinite mode, the Wins persist forever. Therefore, pilots are encouraged to destroy the Core as soon as possible.