Alchemist's Oasis

Alchemist's Oasis enters the battlefield tapped.
When Alchemist's Oasis enters the battlefield,
choose a basic land type. It becomes that type.
{1},{t}: Change the basic land type of Alchemist's
Oasis.
{x},Sac: Search your library for X basic lands. Put
one into your hand, one on the battlefield, then shuffle your library and put the rest on top
of your library.