The Spellican resembles a large bird in a generic mage's cloak and hat. Its arm-like wings are lined with piano keys, and end in five feathered fingers. The bottom of its body hides it feet (assuming it has feet) and is decorated with bells. It wears a wig-like spellbook underneath its hat, with the pages resembling hair. Underneath its beak, it has a curled, yellow pouch-like part on its neck. It carries a broom with it, which has a purple shaft and a glass-looking sphere on one end.
The Dream Eater's name is a portmanteau of "spell" and "pelican".
 Kingdom Hearts 3D: Dream Drop Distance
When Sora and Riku each make their second visit to Traverse Town, Joshua tells them that his friends, who have each reunited with their partners, have a new mission: to take out a powerful Dream Eater that has appeared in the town. This Dream Eater is capable of summoning other Dream Eaters, which it sends to fight in its place. Joshua asks both Sora and Riku to help defeat the new Dream Eater.
In Sora's incarnation of the town, the Spellican appears high over the Fountain Square, where it summons a crowd of Dream Eaters to attack Neku and Shiki, after which it disappears. It crosses over to Riku's incarnation of the town, where it attacks Beat and Rhyme. Riku comes to help, but the three of them become engrossed in their conversation, and the Spellican throws a tantrum when it is ignored. It summons more Dream Eaters before fleeing the square, with Riku in pursuit. In the Side Street, the Spellican summons a stampede of Cera Terror to attack Riku, but Riku fends them off and heads the Spellican off in the Third District. Before he can attack it, the Spellican crosses back to Sora's incarnation of Traverse Town, where it summons the Hockomonkey, Wargoyle and Char Clawbster to attack Sora. Sora defeats them all, but the Spellican leaves Traverse Town altogether and heads for the Symphony of Sorcery. To keep his friends from failing their mission, Sora offers to go after the Spellican for them.
The Dream Eater arrives just as Mickey, as the Sorcerer's Apprentice, is casting a multitude of spells using the power of Yen Sid's hat. It enters the musical realm and uses its powers to trap Mickey in an endless nightmare. Sora arrives shortly after and finds that the musical score which grants entry to The Sorcerer's Appentice part of Symphony of Sorcery has been corrupted by the power of darkness. Mickey asks Sora to enter the world and find a Sound Idea, the only thing capable of cleansing the darkness plaguing the score. Sora brings the Sound Idea to Mickey, the dark barrier is purged when the Sound Idea from Riku's version manifests as the two Sound Ideas form a harmony. Sora then enters the musical score to defeat the Spellican in a strenuous fight, releasing Mickey.
The battle against the Spellican can take a while, so Sora should go in with either a full Drop Gauge, Drop-Me-Not commands, or Wake-up Block. Although, Spellican can be affected by Magnet and Zero Gravity, so, Zero Graviga and Collision Magnet are very useful and must be equipped. Using these attacks can make the battle quicker. Although, be aware that Zero Graviza and Magnet Spiral Doesn't affect Spellican. Sonic Blade must also be equipped in the deck, since Spellican can be made to flinch with nearly any of Sora's attacks, interrupting his own attacks, and as this command hits multiple times, its almost certain to flinch him, opening it up for more hits from Sora. It's also important to equip all Combo Plus and Air Combo Plus available, as well as using Spirit's with Light Screen and Attack Haste, allowing for a better defense and a more effective attack.
The battle begins along a road of light, on which Sora is sliding to chase down the Spellican. Sora must dodge or destroy the projectiles the Spellican fires while constantly boosting with in order to catch up to the Spellican. Sora just need to pass trough Spellican to make it transport both of them to the main battle arena. But once the Spellican is in range, Sora should use a Flowmotion attack, such as Sliding or Kick Dive, since it will do heavy damage to Spellican.
The main battle arena is filled with floating rocks that can be used as stepping stones to perform Flowmotion attacks or navigation, or also as barriers against Spellican's attacks.
The Spellican frequently warps around the area and attacks by firing shooting stars that homing in on Sora, which can be easily avoided with Dodge Roll, or transforming its staff into a lengthy blade of light that it will swing wildly, which can be blocked. Spellican will always try to teleport or ride it's magic broom right after doing an attack, so it's important to use either Collision Magnet or Zero Graviga just after evading his attacks. Those commands, if well timed, can also interrupt Spellican's attacks. Collision Magnet can be used to draw Spellican near Sora, which will then launch him away. After this attack, Spellican will remain on the ground, open for combos and Sonic Blade. It's also possible to use Zero Graviga on him on this state, and if well timed, right after finishing a combo. Then, he willl stay floating on the air, open for more combos.
Once the Nightmare has lost most of its health, it will begin summoning meteors after darkening the sky. On occasion, the Spellican will sweep purple dust balls, which turn into purple lightning-slinging magic brooms . Even if Sora doesn't destroy all of them, Spellican will reappear after some time.
After enough time passes, or after taking enough damage, the Spellican will take Sora with it back to the celestial road, where he will need to chase it down again in order to continue the battle. Although, Spellican can be finished before this happens.
On the Secret Portal rematch, Spellican has much more HP and is more powerful. So, Sora must buy the highest Attack Gain and Drop Decelerator and put Spirits in the party that has Attack Haste, Magic Haste, Light Screen and Attack Boost before the battle, in order to provide a proper attack and defense, as well as making sure to install at least one Collision Magnet, Zero Graviga, Sonic Blade, Ars Arcanum, and Curaga.