Happiny has a pink, egg-shaped body. She has a red pouch that covers the bottom half of her body. There are three round bumps on Happiny's forehead, and she has a pigtail of hair on her head. Happiny has stubby limbs and is normally seen carrying an Oval Stone in her pouch.
In the series, Brock won an egg in a dress-up contest with the help of Croagunk, which the egg hatches into a Happiny.
Brock's Happiny has been shown to have extraordinary strength, carrying massive loads with relative ease in spite of its small size. It's not certain whether or not all Happiny have strength like this (Note: In the video games Happiny cannot learn Strength via HM however, its evolved forms Chansey and Blissey can learn Strength, It is possible that Happiny could have inherited it as an Egg Move, though it is unknown if this true for the anime).
Happiny evolves into Chansey when leveled up during the day while holding an Oval Stone.