When Crookshank Kobolds enters the battlefield, Cloudstone Curio and Seed the Land trigger.
Resolve the Cloudstone Curio trigger, choosing to return nothing to your hand.
Resolve the Seed the Land trigger, creating a 1/1 Snake creature token.
When the Snake enters the battlefield, Cloudstone Curio triggers, returning Crookshank Kobolds from the battlefield to your hand.
Repeat.
This loop relies on the clever interplay between Ashaya, Soul of the Wild turning your creatures into lands and Cloudstone Curio bouncing your free spells. By casting the zero-mana Crookshank Kobolds, you trigger Seed the Land, which brings a Snake token into play. Because Ashaya makes that token a Forest land, its arrival satisfies Cloudstone Curio's type-matching requirement to safely return the Kobolds to your hand—ready to be cast all over again for an endless chain of landfall triggers and creature tokens.