Episode 33 of The Trigan Empire
aka The Wish Fulfiller
The Black Box
De magische doos (Dutch title)
The Magic Box (Dutch title, translated)
Der Geheimnisvolle Kasten (German title)
The Mysterious Box (German title, translated)
Written by Mike Butterworth
Illustrated by Don Lawrence
It is reprinted in Volume 8 of The Trigan Empire—The Collection (the Don Lawrence Collection).
It is reprinted in Volume 3 of The Rise and Fall of the Trigan Empire (Rebellion).
Plot summary (Dutch)
MediaFire via British Comics Compilations