CLOSE RELATIVES: Eely-Mouth.
SKILLS AND ATTACKS: Static Shock.
STRENGTHS: Agile and fast underwater, also invincible.
WEAKNESSES: Unagi can't resist going for a bite to eat.
BACKGROUND: Unagi is the eel that sank the Jolly Roger Pirate Ship in Jolly Roger Bay. He then made it his home. He is quite smart for an eel, considering he managed to stash one Star in the ship under a Chest-combination lock. Afterwards, he kept the star with him at all times and zapped Mario when he touched him by accident. Unagi is invincible and can't be beaten, just outsmarted.
In the very first Mario 64, Unagi was an eel. Duh. But seriously, he had googly eyes, sorta
like Chain Chomp. His other main features were the fact that he had very sharp looking teeth.
He was also a dark purple in colour.
In Mario DS, Unagi was basically the same, this time he is much brighter. The strategy for beating him was the same.
Unagis returned again in New Super Mario Bros where they are more plentiful and can be beaten with fire.