Beacon to the Immortal Sun

When Beacon to the Immortal Sun enters the battlefield, choose one:
- Lands and artifacts cannot tap to add {w}
- Lands and artifacts cannot tap to add {u}
- Lands and artifacts cannot tap to add {g}
- Lands and artifacts cannot tap to add {b}
- Lands and artifacts cannot tap to add {r}
Then, Beacon to the Immortal Sun perpetually
gains the chosen ability and perpetually loses
all other abilities.