$2.47 @ TCGplayer
All Slivers have "When this permanent enters the battlefield, destroy target artifact or enchantment."
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 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.
The controller of the Sliver that enters the battlefield, not the controller of Harmonic Sliver, chooses the target.
This ability will trigger when Harmonic Sliver enters the battlefield.
