The Octopians are a race of creatures resembling an octopus that appear in the Season 7 episode "A Long Tale For Grandpa". They live on Thunder Island, along with the Meek Meeks, the Grundels and the Thunder Tree, which is protected by their leader Lord Squird with his loyal soldiers.
In "A Long Tale For Grandpa", the Smurfs encounter the Octopians as they travel to Thunder Island to get the Thunder Tree sap that they need to defeat the aphids invading the Smurf Village. The Octopians capture them and place them in a jail inside the Crystal Castle, but the Smurfs escape with the help of Meek Meek, and also manage to hold off the Octopians by spraying the sap drops from the Thunder Tree in their faces.