Sidewinder Sliver
Creature — Sliver
All Sliver creatures have flanking. (Whenever a creature without flanking blocks a Sliver, the blocking creature gets -1/-1 until end of turn.)
"They encircled our patrol with the stealth of snakes, corralling us like livestock." —Merrik Aidar, Benalish patrol
イラスト：
Time Spiral#41コモン英語適正
裁定
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.
Once a Sliver has become blocked by a creature without flanking, the blocking creature gets -1/-1 even if the blocked Sliver loses flanking before the ability resolves.