Hydrox, the defunct chocolate-sandwich wafer, is returning for one more rematch with its nemesis, the Oreo.

Bowing to more than 1,300 phone inquiries, an online petition with more than 1,000 signatures and Internet chat sites lamenting the demise of the snack, Kellogg Co. has decided to temporarily relaunch Hydrox, the left-for-dead cookie.

"These...