The Chaser Spider Viral Core (チェイサースパイダーバイラルコア Cheisā Supaidā Bairaru Koa) is a sentient, chrome Viral Core that summons the E-Circular and turns Mashin Chaser into his Tune Chaser Spider form, equipping him with the pincer-like Fang Spidey. When initiating Triple Tune, Chaser inserts this Core first.
Chaser Spider came second in a succession of the three Viral Cores used by Mashin Chaser as he came to the aid of Scooper against Kamen Rider Drive. How Was That Decisive Moment Captured?
Engaging a pair of Core-less Low-Class Roidmudes, Bat-Type and Cobra-Type, which had been created by Kamen Rider Lupin, Mashin Chaser fittingly wielded the Fang Spidey to destroy them both. Kamen Rider Drive: The Challenge from Lupin
Following Chase's sacrifice, the three Chaser Viral Cores returned to save Kamen Rider Mach from Gold Drive. Why Must They Fight?