As the name states, Ghost Whale is a giant, robotic whale. It has several hues of purple on its sides, back, and tail. It has a giant red jewel on its head, tan teeth, and green eyes. It has light-purple wheels on its side and peach colored stripes most of the places. It has yellow blowholes on its back.
The inside of Ghost Whale has several shades of green and has mostly water on the floor (due to it being on the ocean). Red wires are also inside the robot.
When starting this battle, Sonic or Blaze will be trapped on a block of ice while robotic fish will try to distract the player. However, these enemies can be beaten with a simple attack.
This boss is fairly simple. First, the Ghost will swim up to the ice floe the player is standing on and bite a chunk off. At this time, the player must hit the jewel on his forehead to stun him, and he will open his mouth. When the player enters his mouth, they get a time limit before the Ghost Whale expels the player. This time can be increased by destroying grey nodes inside the Ghost Whale. The player must then navigate through the Ghost Whale to find the "heart". Along the way, the Ghost Whale will use its internal defenses, such other robots, missiles (which double as platforms), ice patches or electric currents to slow down the player.
Once the heart is found, the player must attack it, and the Ghost Whale will spit the player out through his blowhole. This process must be repeated twice. Each time the player enters the Ghost Whale, the path to the "heart" becomes slightly harder, with a different layout. Also, each time the Ghost Whale spits out the player, it smashes a section of the ice floe that the characters stand on; if the boss is not defeated before the entire ice floe is destroyed, then the player loses a life. After 3 hits, the Ghost Whale will be immobilized until the player jumps to hit the jewel on his forehead one last time. After that hit, he will explode.
On normal difficulty, the fish-like robots that spawn in the ice floe section come in groups of three and two (for last phase) as opposed to two and one (last phase). There are less time bonus nodes inside the Ghost Whale as well.