Fungus Sliver
{3}{G}
Creature -- Fungus Sliver
2/2
All Sliver creatures have "Whenever ~this~ is dealt damage, put a +1/+1 counter on it." (It must survive the damage to get the counter.)
Spiteful Sliver
{2}{R}
Creature -- Sliver
2/2
Sliver creatures you control have "Whenever ~this~ is dealt damage, it deals that much damage to target player or planeswalker."