Ring of the Octopus King
| "A mermaid who fancied to sing,|
Roused lust in the Octopus King.
There are technically eight different rings of the Octopus King. It is possible to find more than one in a single game, but finding all eight is extraordinarily unlikely. These rings are obviously more desirable than their mundane counterparts, but the additional effects these rings offer are very minor. It's not uncommon to find superior randart rings.
The rings of the Octopus King were added in 0.10.