Sunkern is a mostly yellow, seed-like Pokémon with a small sprout growing out of its top. It has triangular, spike-like protrusions on top of its head, encircling the sprout. Its body has three broad, brown, vertical stripes. Two of the stripes start jaggedly above Sunkern’s dark eyes and continue downward. The other stripe is directly below Sunkern’s mouth. Since Sunkern’s eyelids are brown, the brown streak patterning appears uninterrupted when Sunkern’s eyes are closed.

Sunkern is known to be very weak. Aware of its weakness, it only feeds until it evolves. However, it feeds on only the dew from under the leaves of plants. It tries to move as little as possible since it tries to conserve all the nutrients it has stored in its body for evolution. If attacked, it shakes its leaves at the attacker. Sunkern occasionally falls from the sky on early mornings for unknown reasons. A year after a cold summer, the population of Sunkern explodes