Skulking Sliver

Slivers you control have skulk.
"They broke through the blockade like a hot knife
through cheese. They had killed ten, no, twenty before
we had even noticed they were there. They blend into
the shadows, slither by underfoot, wait for the perfect
moment to strike. These abominations have evolved.
They're no longer the brutal slaughterers they once
were. They've become deadly efficient killers."
— Bloodied Journal, Anonymous Author