Spiteful Sliver

Creature — Sliver

Sliver creatures you control have "Whenever this creature is dealt damage, it deals that much damage to target player or planeswalker."

2/2

2019-06-14:
The ability granted by Spiteful Sliver will trigger even if the Sliver is dealt lethal damage. For example, if a 2/2 Sliver blocks a 7/7 creature, the Sliver’s ability will trigger and it will deal 7 damage.
2019-06-14:
Damage dealt by the Sliver due to its triggered ability isn’t combat damage, even if it was combat damage that caused that ability to trigger.
2019-06-14:
If a Sliver is dealt damage by multiple sources at once (such as by two creatures blocking it), its ability triggers once and one target is dealt that much damage.