Thor, Vol. 1 #468 (1993)

Blood and Thunder - Part 1: Distant Thunder
Mad God: Part 1 (of 13) - The Silver Surfer guest stars in part one of this cosmic crossover - involving Thor, Silver Surfer, Warlock Chronicles, and Warlock & the Infinity Watch! The action begins when Sif and Beta Ray Bill encounter Thor, who is frantically attempting to end the madness that consumes him. But wait, there's more!
Release Date: 1993