Twilight Thorn

The Twilight Thorn is a boss from Kingdom Hearts II.

The Twilight Thorn is a giant Nobody that attacks with lightning-like thorns, and shares properties with other deformed Nobodies: it can stretch and contort its body and possesses remarkable maneuverability.

Only one appears, in Kingdom Hearts II, when Roxas goes to the Station of Awakening. It is interesting to note that when Roxas senses a presence and turns around to see who it is, he sees a person wearing an Organization cloak, just before it turns into the Twilight Thorn. Judging from the figure, it seems to be none other than Roxas himself. It is unknown if anymore Twilight Thorns will appear in the series.

The Twilight Thorn shares many notable similarities with Darkside, a gigantic humanoid Heartless. Both prominently appear in Roxas and Sora's awakenings, respectively, and are the first bosses of the game. They also seem to share close connections with Roxas and Sora (again, respectively): the Twilight Thorn appears as Roxas' former self, while Darkside is born from Sora's shadow. The two are also both able to summon lesser Heartless/Nobodies to attack.

At the same time, the two creatures share key differences, being a Nobody and a Heartless. Darkside has wild, unkempt hair that covers its face save for two yellow eyes, while the Twilight Thorn has wild blue scarves around its neck, and lacks a face of its own.

Note: The Twilight Thorn is not registered in Jiminy's journal until you enter the Simulated Twilight Town. This is strange because Sora doesn't meet the Twilight Thorn. However, this may be Roxas's memory of his own Awakening instead. Twilight Thorn may be the Nobody of a person that turns into a Darkside.

Journal Entry
A giant Nobody who Roxas fought at the Station of Awakening.

Although it tried to capture Roxas with its thorns, it was overpowered and defeated by the strength of the Keyblade master.

Trivia

 * As noted, the Darkside Heartless and Twilight Thorn both share thematic similarities. It should also be noted that the Twilight Thorn's name can also be interpreted from the Japanese katakana as "Twilight Zone," giving its name a similar meaning to Darkside's.
 * It is also speculated by fans that Twilight Thorn Nobodies had Marluxia as their master, given Marluxia's love of roses and element of Flower (His death before Roxas fought it could say that this one was controlled by another Organization member, most likely Xemnas. It could also be a reflection of Sora's fleeting memories of the Organization, especially Marluxia, considering the stance of the Awakening as a "world.")
 * During the cutscene that he appears in a second right before he appears you see the back of a organzation member who this is is never reavealed. However this member is often considered a piece of Roxas' past.