Pokémon Go ‘Spelunker’s Cove’ event and Timed Research tasks
From June 15-18, rock- and water-type Pokémon will be spawning in high numbers in Pokémon Go for the “Spelunker’s Cove” event.
This article references relevant content from the polygon.com website. Original article link: [https://www.polygon.com/pokemon-go-guide/2024/6/14/24178461/spelunkers-cove-event-timed-research-shiny-crabrawler]

Pokémon Go is hosting a water- and rock-type Pokémon event called “Spelunker’s Cove” to coincide with Pokémon Go Fest: Madrid. The event runs from June 15-18 and boosts the spawn rates of the aforementioned types of Pokémon.
During the event period, any candy obtained from catching Pokémon will be doubled. Crabrawler is also making its shiny debut, so if you’re super lucky, you may see a shiny one.

Below we list out the other perks alongside Pokémon Go’s “Spelunker’s Cove” event, including the paid Timed Research, event Field Research Tasks, and spawns.
Pokémon Go ‘Spelunker’s Cove’ event Timed Research and rewards
This is a paid Timed Research for $1.99. Is the “Spelunker’s Cove” paid research worth buying? While the battle passes make it worth the value, we don’t recommend shelling out this extra cash unless you really want guaranteed Crabrawler encounters.
Rewards: 3 Premium Battle Passes, Crabrawler encounter, 20 Crabrawler Candy
Pokémon Go ‘Spelunker’s Cove’ event Field Research and rewards
Spinning a PokéStop during the event period may yield one of these tasks:
Pokémon Go ‘Spelunker’s Cove’ event boosted spawns
These Pokémon will spawn more frequently during the event period:
Pokémon Go ‘Spelunker’s Cove’ event raid targets
These Pokémon will be in raids during the event: