Blur Sliver

Sliver creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Traveling across the desert alone, you might assume you'd see them coming, but that would be your third mistake.

Commander Masters

They move in a synchronized swarm, turning entire squads into heaps of bloody rags and bones in an instant.

Secret Lair Drop

Jumpstart: Historic Horizons

Magic 2014

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.

If Blur Sliver leaves the battlefield during combat, any attacking Sliver creatures that came under your control this turn will continue to attack, even though they will no longer have haste.

If you change the creature type of a Sliver you control 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 you control.