Charybdis, Vortex Maw

Whenever Charybdis blocks or becomes blocked
by a creature, tap that creature. It doesn't untap during its controller's next untap step.
Whenever Charybdis deals combat damage to a player, shuffle target tapped creature that player controls into its owner's library.
"When she swallowed the seas, her inner vortex could
be seen, and the rock echoed savagely round about"
- Odyssey Book XII