Shifting Sliver

Creature - Sliver

Slivers can't be blocked except by Slivers.

Once the last few slivers the Riptide Project controlled were dead, there was nothing to keep the island from being completely overrun.

2/2

2013-07-01 Abilities that Slivers grant, as well as power/toughness boosts, are cumulative. However, for some abilities, like flying, having more than one instance of the ability doesn't provide any additional benefit.
2013-07-01 If the creature type of a Sliver changes so it's no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.

Card is in preconstructed decks:

mtg.wtf