Pikachu days

A yellow, mouse-like creature with red cheeks and a lightning bolt-shaped tail appears in various settings, initially lying unconscious in a cave, then standing joyfully with arms raised on a sandy surface, followed by a close-up of it winking, then holding a party hat while standing beside a white, star-shaped creature, then being lifted into the air by a boy in a red and white cap, and finally flying through a dark blue sky with stars. The creature is shown in a series of distinct scenes involving different characters and environments.