Bonescythe Sliver
Creature — Sliver
Sliver creatures you control have double strike. (They deal both first-strike and regular combat damage.)
"Their appendages are sharper than our swords and quicker than our bows." —Hastric, Thunian scout
Illustrated by
Duels of the Planeswalkers Promos 2013#1RareEnglishLegality
Rulings
If Bonescythe Sliver leaves the battlefield after other Sliver creatures you control have dealt first-strike damage but before regular combat damage, those Slivers won’t deal regular combat damage (unless they still have double strike for some other reason).
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.
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.