Its Shell Spikes ability makes an opponent discard an energy if its damaged
Pokemon Card Dimensions Breakdown (Height, Width, Thickness) Card Height vs Width Explained Understanding orientation helps when measuring: Height (long edge): 3.5 inches (88 mm) Width (short edge): 2.5 inches (63 mm) Cards are designed vertically (portrait orientation), which influences artwork layout and gameplay readability
Even with how much devotion to black it gives you and how cool it is, most of the price comes from its place on the Reserved List
Those free spells often include ramp, removal, or more creatures, so its a huge tempo swing
From there, it explodes into a myriad of other rarities, many focusing on distinct foiling patterns like Ultimate Rare (embossed foil), Ghost Rare (a 3D holographic image), Collector's Rare, the recent Quarter Century Secret Rare, and Platinum Secret Rare