This is the first creature Ecco is able to transform into. As a seagull, Ecco shrinks to a fraction of his original size and can fly over cliffs and other physical obstacles that are impossible for him to pass as a dolphin. As a seagull, Ecco is not a strong flier and takes time to gaine altitude. Although Ecco does not take physical damage in this form, the transformation will be ended the instant he makes physical contact with anything. In flight, Ecco will have to dodge falling rocks and will also be attacked by swooping eagles. If hit, Ecco will fall straight down and land in the water. If the player holds down in a diagonal direction and press B on the controller, Ecco will make a short dive in that direction. This is useful for dodging rocks and eagles.
The second transformation in the game is a jellyfish. This transformation is accessed for the first time in the Vents of Medusa level. As a jellyfish, Ecco can slowly move right, left and down. Holding up and pressing the B button will make Ecco propel himself upwards in the direction desired. If while propelling himself, Ecco makes contact with the ceiling, he will bounce off it and sink a little. In this form Ecco will be attacked by dolphins with their sonar. Ecco can not deal damage in this form, but he does not require oxygen.
Later in the game Ecco will be able to turn into a shark. As a shark Ecco does not need oxygen, however he can not use his sonar, charge attack, or increase his swimming speed. Ecco's swimming pattern changes and he can no longer swim on diagonals. Instead he must swim left and right to go up and down. Other sharks will not harm Ecco in this form but he will get attacked by dolphins. Ecco can use the shark's bite attack to fight other creatures.