This creature is based off the mythological Kraken, a gigantic squid capable of swallowing entire ships. The Cracken in the Fairly OddParents is equally as vicious, and attacks Timmy Turner and his fairies throughout the episode.
It is a gigantic squid-like creature that is colored green.
This creature appeared in "Beach Blanket Bozos". Timmy Turner wished for a super-scary surf course for his parents so that they would stop surfing and end the wish limbo, Cosmo included this creature in it. The Cracken grabbed Timmy, Cosmo, Wanda and Poof with his tentacles, and Mom and Dad decided to stop competing with each other to save their son and "those green, pink and purple sea creatures". But after giving up with the competition, they became lousy surfers again, and could only throw seaweed at him. The Cracken was about to eat Timmy's parents until he wished for a giant wave to take the Cracken away. Later at the Luau, Timmy wanted to get " crackin' ", so Cosmo poofed up the Cracken again and it mauled Cosmo.
He was credited as "Cracken" and not as "Kraken", due to the pun made at the end of the episode.