Like Navel Rock, Birth Island is invisible on the Town MapFRLG by default due to its event-only status, only appearing when the player first arrives there. This is in contrast to the other Sevii Islands, which appear on the Town Map even before the player has visited them. It also never appears on the PokéNav's map.E
Upon first arriving at the island, the only thing the player will find is an inert, black, triangular rock. To make Deoxys appear, the player must solve a strange puzzle by following the rock: each time the rock is interacted with, it will move to a different position on the island, and the player must perform the shortest possible path to the rock's new position. Each successful interaction will cause the rock to glow more; the puzzle is solved once the rock returns to one space above its original position and glows a bright red. Interacting with the rock in this state will cause it to shatter and Deoxys to appear. If the player fails to follow the shortest path before the puzzle is solved, interacting with the rock will reset the puzzle, moving the rock back to its original position and reverting it to black.
To solve the puzzle and make Deoxys appear, the player must do the following:
Approach the triangle from below and press A.
Press ← 5×, ↓ once, then A.
Press → 5×, ↑ 5×, then A.
Press → 5×, ↓ 5×, then A.
Press ↑ 3×, ← 7×, then A.
Press → 5×, then A.
Press ← 3×, ↓ 2×, then A.
Press ↓ once, ← 4×, then A.
Press → 7×, then A.
Press ← 4×, ↓ once, then A.
Press ↑ 4×, then A.
When encountered in the wild, Deoxys will appear in Normal Forme, but once captured, it will transform into Attack Forme, Defense Forme, or Speed Forme. In Pokémon FireRed and LeafGreen it will transform into Attack Forme and Defense Forme respectively, and in Pokémon Emerald it will transform into Speed Forme.
Birth Island appeared in the FireRed & LeafGreen chapter. After battling against Red, Organism No. 2 retired to the Birth Island in order to heal the damage it had received when Pika's Thunder struck its core. In order to protect itself, Organism No. 2 encased itself in a pyramid-like protection called "Delta Shield", a combination of Reflect and Light Screen. Giovanni, however, took advantage of Organism No. 2's weakened state, and followed it. Using his Beedrill's Agility to cut down its movements and his Aggron's Brick Break to destroy the Delta Shield, Giovanni was able to capture Organism No. 2 with a Poké Ball specifically designed to catch the DNA Pokémon.