The Spider Imagin is an Imagin and the main antagonist of episodes 25 and 26 of Kamen Rider Den-O.
Kamen Rider Den-O
The Spider Imagin made a contract with Masashi, who wished for his sister Mayu to see a star. However, Spider went about fulfilling the wish by tying her to a radio tower. The Imagin was initially defeated by Zeronos, but prior to the fight the Imagin split itself in two, with the second Spider Imagin outliving the first one.
The second Spider Imagin attempted to fulfill the wish by destroying an electricity pylon, causing massive blackout throughout the district. The Spider Imagin later battled Den-O Gun Form before future Zeronos interfered in the fight and the Imagin was destroyed by Sword-Form.
The Spider Imagin later appeared in the Kamen Rider Den-O Hyper Battle Video as one of the Imagin aboard the DenLiner.
Kamen Rider Decade
The Spider Imagin was one of the Imagin that attempted to get Natsumi Hikari to tell them her wish while she was trapped in shifting dimensions during the destruction of the worlds.