Claws
Claws, something they share, even if in different ways.
If Victor's claws are almost cat-like, James', even when they were made of simple bone, are like sharp knives.
Hitting you they give you different sensations: Logan's feel like a clean, surgical cut, Creed's, instead, feel like a prolonged rape.
Fingertips and hands bloodily sinking into meat, so completely different from Logan.
They rip your skin, sink into your body and it's not a merciful death, it's perverted violence that strikes on you, like a rabid beast.
Creed's claws aren't like Wolverine's adamantium blades: they're pure and simple weapons to dismember.