From Glitch City Laboratories
"Wild appeared!" is the result of when the player uses a glitch or a game-altering device to enter a battle with no Pokémon in his or her party. The name originates from what text the game displays when the battle starts, though what it exactly shows has more spaces between "Wild" and "appeared!".
When this happens in Generation I Pokémon games, a variation of the TMTRAINER effect happens, where the game may freeze or the player eventually defeats the opponent by using a Super Glitch move. In Generation III Pokémon games, a Decamark appears, of HEX number 0000.
The only known methods of entering a wild Pokémon battle with no Pokémon in battle (without the use of a game-altering device) is by exploiting the walk around with only fainted Pokémon glitch in the Generation I games, or utilising the Pomeg Berry Glitch in Pokemon Emerald or Generation IV.
See also
- Spacing syntax glitch