Mogglings have been known to play ball with hibernating slivers, completely unaware of their true nature.

Hibernation Sliver

All Slivers have "Pay 2 life: Return this permanent to its owner's hand."

Commander Masters

Secret Lair Drop

Tempest Remastered

Premium Deck Series: Slivers

Stronghold

Each Sliver gains "Pay 2 life: Return this creature to owner's hand."

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.