The cave is two levels high, contains several stat-boosting items, and the only wild Pokémon found inside is Smeargle. This is the only area in the third generation core series games (other than via the unused Altering Cave event) where the player can find Smeargle.
Angered by this, Spenser, Brandon, Tucker, and Lucy attacked Guile Hideout, but he easily reflected all of their Pokémon's attacks right back at them with his sword without getting even scratched. While Greta used her Umbreon's Double Team to distract the rental Pokémon, Anabel used her Raikou's Thunder Shock to trap Guile in an electrical cage, leaving Emerald alone to focus on capturing Jirachi without distractions. After weakening Jirachi using Crystal's Bonee and Monlee, he attempted to capture it with a Luxury Ball. Although Jirachi went into the Poké Ball, Guile Hideout used his Surskit's Psybeam to prevent the ball from closing and then destroy it. He then broke free from the electrical cage and tried to attack everyone with his sword, but Emerald's Sceptile, Sudowoodo, and Dusclops protected them. When Guile tried to snatch Jirachi, it disappeared, and he left the cave to continue pursuing it.
Later, Noland was revealed to have visited the cave and captured three Smeargle living there, due to them having Sketched Jirachi's Wish, which he hoped to use to find Jirachi before Guile.