Slivers are often seen toying with enemies they capture, not out of cruelty, but to fully learn their physical capabilities.

Constricting Sliver

Sliver creatures you control have "When this creature enters, you may exile target creature an opponent controls until this creature leaves the battlefield."

Sliver creatures you control have "When this creature enters the battlefield, you may exile target creature an opponent controls until this creature leaves the battlefield."

The List

Newborn slivers will sometimes wrap themselves playfully around a human's finger. They grow out of the "playful" part.