Clashing Sliver

All Sliver creatures have "{t}: Add one mana of
any color." and "{0}: This creature gets +1/-1 or
-1/+1 until end of turn."
All Sliver creatures are Elementals in addition to
their other types.
When Clashing Sliver enters the battlefield,
choose blue or red. All Sliver creatures have protection from the chosen color and can't gain protection from the other.