An Oval Stone is a held item that makes certain Pokemon evolve
Hapiny + Oval Stone = Chancey
The Oval stone evolves Happiny into Chansey.
Chansey evolves from an Oval Stone.
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.
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 can evolve happiny with an oval stone after its friendship is high
The oval stone evolves happiny into chansey but only if it has anof happiness
you give the oval stone to happiny and makeit have high friendship at day
Happiny uses the Oval Stone to evolve into Chansey.