Summer Cooler is a Legends of Idleon item: dropped by 1 monster, quest reward, sold in shops. Hold down to open for a random reward! Or, hold down for a LONG time to open them faster.

Summer Cooler | Idleon Toolbox

Hold down to open for a random reward! Or, hold down for a LONG time to open them faster.

Summer_Cooler

Hold down to summon a bunch of Summer Monsters, and get a random Pearl!

Beach_Oyster

Coastiolyte

Cooler_than_a_Cooler!

Clear the beach of all these 'Out of Towner' monsters, namely 5 Plasti Dougs and 5 Mr Blueberry's