| Pokedex Entries: |
| Red | As it grows, the stone portions of its body harden to become similar to a diamond, but colored black. |
| Blue |
| Yellow | Burrows at high speed in search of food. The tunnels it leaves are used as homes by Digletts. |
| Gold | It twists and squirms through the ground. The thunderous roar of its tunneling echoes a long way. |
| Silver | It rapidly bores through the ground at 50 mph by squirming and twisting its massive, rugged body. |
| Crystal | As it digs through the ground, it absorbs many hard objects. This is what makes its body so solid. |
| Ruby | ONIX has a magnet in its brain. It acts as a compass so that this POKéMON does not lose direction while it is tunneling. As it grows older, its body becomes increasingly rounder and smoother. |
| Sapphire |
| Emerald | There is a magnet in its brain that prevents an ONIX from losing direction while tunneling. As it grows older, its body becomes steadily rounder and smoother. |
| FireRed | It usually lives underground. It searches for food while boring its way through the ground at 50 miles per hour. |
| LeafGreen | As it grows, the stone portions of its body harden to become similar to a diamond, but colored black. |
| Diamond | When it travels underground, it causes rumbling and tremors. It can move at 50 mph. |
| Pearl | It squirms through the ground using its long and rugged body. It always eats while burrowing. |
| Platinum | It burrows through the ground at a speed of 50 mph while feeding on large boulders. |
| Stadium 1 | Its large body is over 26 feet long. Despite its size, it can squirm its way through the ground at 50 mph. |
| Stadium 2 | It twists and squirms through the ground. The thunderous roar of its tunneling echoes a long way. |
| TCG | Onix: This Pokémon burrows through the earth at high speed, looking for food. The tunnels it digs are used by Digletts as nests. |
