As a promotional card inserted in Japan’s **CoroCoro Comics** magazine in 1998, Brock’s Onix (Glossy) is a classic Japanese **Pokémon TCG** trading card featuring Gym Leader Brock’s signature rock-type. Its illustration by Ken Sugimori depicts Onix coiled against a dark, holographic background – a bold example of late-’90s Pokémon artwork. The card’s shimmering holofoil pattern (often called “Glossy”) and Brock’s trainer portrait reinforce its Gym Leader theme, making it visually distinctive. Collectors prize this rare magazine-exclusive promo for its nostalgic appeal and scarcity – it even predates Brock’s Onix appearances in English sets. With 100 HP and a basic Rock Throw attack, it reflects the straightforward gameplay of the era, but its true charm is as a vintage **Pokémon TCG** collectible.