Give it to Happiny and level it up during the day to evolve it into a Chansey.
Chansey evolves from an Oval Stone.
Hapiny + Oval Stone = Chancey
The Oval stone evolves Happiny into Chansey.
happini can evolve with a oval stone
Do you mean what is an oval stone? Well, an oval stone is an item that when held by a Happiny during the Daytime and leveling it up evolves it into Chansey.
Happiny---->Chansey using the oval stone.
An Oval Stone is a held item that makes certain Pokemon evolve
The only Pokemon that can be evolved with an Oval stone is a Happiny into a Chancey.
Happiny evolves into Chansey with an Oval Stone.
you give the oval stone to happiny and makeit have high friendship at day
The oval stone evolves happiny into chansey but only if it has anof happiness
Happiny uses the Oval Stone to evolve into Chansey.