Shaded Citadel

Shaded Citadel enters the battlefield tapped.
1 Region Owned: All Spiders gain +1/+0
2 Regions Owned: {t}: {b} All Spiders gain
+1/+0
4+ Regions Owned: {t}: {b} All Spiders gain +2/+0
(Only 4 regions may be on the battlefield at once)