Octoson Tentacles was the alcoholic, druggie, abusive father of Squidward Tentacles. According to Spongebob Squarepants, he never hugged his son and beat him and his wife. On Spongebob Squarepant's TVTropes page, Octoson has been tagged as a "Complete Monster". This is true - he has very little if any redeeming qualities.
He was an old, grey haired man who smoked frequently. He had a Brooklyn accent. Despite his upper body looking human, he has the lower body of a squid - he was a squid who initially found Tony Tony Chopper's dead body after the War of the Gobi Desert and absorbed his Devil Fruit, the Human Human Fruit, from him.
On October 12, 2009, mafia member Mihoko Fukuji of the Fukuji mafia family shot him to death with an old fashioned pistol in a back alley after failing to repay the right amount of money to the Fukujis. When Squidward was asked what he thought of his father's death, he replied:
"I highly thank miss Fukuji for killing that monster. She is closure for me to be rid of such a horrible human being. Thank you Fukuji, you've done the thing I've needed to do but couldn't bring myself to do for so long."