A new special event begins in Pokémon Go this week, and it’s all about the rock-type Pokémon. “Adventure Week,” as developer Niantic has dubbed the campaign, encourages players to get outdoors and start digging around for Omanyte, Kabuto, Aerodactyl and other uncommon, fossil-based monsters.

These Pokémon, along with the non-fossilized Onix and Sudowoodo, will be more common than usual throughout the week. The entire event runs from May 18 at 1 p.m. PT until May 25 at 1 p.m. PT, giving players the full seven days to fill out their rock-type collections.

PokéStops will dole out more items than usual to help out with this. As a bonus, buddy Pokémon will also need to travel a shorter distance to collect candy. To top it all off, all players who log in during Adventure Week will get a special item of clothing to commemorate the event: the Adventurer’s Hat.

As summer nears, expect there to be more reasons like this to start heading out with Pokémon Go again. The game’s first sponsored outdoor event ran earlier this month in North Carolina; Niantic has yet to announce another, but the company has spoken about its hopes to continue bringing players together in the past.