Starwalker was added in Beta 30.0. Previous Versions can be found here.
Since Beta 53.0, Starwalker is a Common monster with a Magic effect that only works if your deck lacks any Rare and Epic cards, exactly like Starwalker Bird, making them work very well together.
On its own, it is a solid 4/4/4. But through this restriction, it allows you to return a card of your choice from your hand to your deck and have its cost reduced by 4G, giving a full refund. This makes it work somewhat like a mix of Malius and an older version of Editor 2.