TOI-3321 is a Sun-like G-type star (about 1.04 solar masses, 5,850 K, 1.55 solar radii), 286 light-years from Earth. TOI-3321 b is a 0.55-Jupiter-mass companion, with an orbital period of 3.7 days, at 0.047 AU from its star, and an equilibrium temperature near 1,616 K, on an eccentric orbit (e ≈ 0.05), discovered in 2024 via transit. The inner world is a hot Jupiter — a gas giant hugging its star at a fraction of Mercury's distance — a class that forced astronomers to rethink how giant planets form and migrate inward.