Petilil is a Grass-Type Pokémon in Pokémon Legends: Arceus that evolves into Hisuian Lilligant, a Grass and Fighting-Type Pokémon that is strong against Ground, Water, Grass, Electric, Rock, and Dark-type Moves. Trainers can catch wild Petilil primarily near the Holm of Trials and at the Cottonsedge Prairie, two locations within the Crimson Mirelands. When captured, Petilil has a slight chance of holding a Lum Berry, which Cherubi in Pokémon Legends: Arceus also can potentially carry. On the other hand, the Bulb Pokémon has a much higher chance of holding a Vivichoke. To lure Petilil into facing a particular direction, players can feed the Grass-Type Pokémon a Springy Mushroom or Crunchy Salt.
Once players have caught a Petilil, they can evolve it into Hisuian Lilligant with a Sun Stone, a rare evolution item that can be procured through several different ways. One method of obtaining a Sun Stone is finding the object as buried treasure with the Ursaluna Mount.
Trainers will unlock Ursaluna during "Arezu's Predicament," the eighth mission of Arceus' main story. After meeting with Warden Calaba on Sludge Mound, players must face off against Ursaluna in battle to calm him down. Afterward, they can ride the Normal and Ground-Type Pokémon whenever they please. However, keep in mind that the buried items Ursaluna discovers are randomized. Hence, finding a Sun Stone in Pokémon Legends: Arceus will be a rare occurrence.
Pokémon Legends: Arceus - Petilil Evolution Guide
Alternatively, the most reliable way of acquiring a Sun Stone is by completing Request 85: "At Home under the Eaves." This quest is unlocked once players have added Psychic-Type Chimecho to their Pokédex and obtained Hisuain Braviary as a Pokémon Ride. By fulfilling Request 85, Trainers are guaranteed to receive a Sun Stone as a reward.
Sun Stones can also be purchased from the Trading Post for 1,000 Merit Points, a currency earned by finding Lost Satchels across Hisui. Ginter from the Ginkgo Guild Shop will occasionally present a Sun Stone as a Special Offer for ₽5,000. Players will know the stone is for sale when Ginter refers to his Special Offer as the "Sunlike Rock."
Trainers may also obtain a Sun Stone while breaking shaking ores in Pokémon Legends: Arceus or exploring a Space-Time Distortion Zone. However, similar to the Ursaluna method, these two techniques wholly rely on RNG for a Sun Stone to appear. Therefore, it is recommended that players focus on finishing Request 85 or making a purchase at Jubilife Village's Trading Post to obtain the Sun Stone for evolving Petilil in Pokémon Legends: Arceus.
Pokémon Legends: Arceus is available on Nintendo Switch.