This is yet another neat monster from Ultra Q. It’s a giant rock that is blown to pieces and reforms as this guy. (The image of him standing is an anomaly, he’s trying to shake off the episode’s protagonist.) This guy is also really menacing; the show’s monsters ranged from evil to sympathetic, but this guy was definitely the former. He uses Godzilla’s trademark roar, however, which is kind of distracting.
The effects are just top-notch. I especially liked the creature’s (more or less) exposed beating heart. This is suffused with light, great lighting effects being a Tsuburaya specialty, along with churning water effects. Whenever I see either of those two things, I am very happy. To my sheer, delight, this episode featured both.