Spinneret Sliver

Swamp

All Slivers have "{T}: Add one mana of any color."

All Sliver creatures have frenzy 1. (Whenever a Sliver attacks and isn't blocked, it gets +1/+0 until end of turn.)

Sliver creatures you control have trample. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

All Slivers have "{1}, Sacrifice this permanent: Each player discards a card."

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

All Sliver creatures have menace. (They can't be blocked except by two or more creatures.)