Superboy Vol. 1 (1949-1976) / Superboy and the Legion of Super-Heroes (1976-1979) #203

Plot

After the Legionnaires run a practice drill on protecting their headquarters, Invisible Kid collapses. He reveals that when he turns invisible he can see an invisible world and one of its inhabitants, Myla. Later, Dream Girl dreams that Validus is coming to attack the Legion. Saturn Girl confirms that the components of Tharok's brain being held by the Legion are summoning Validus. Validus attacks Legion headquarters and kills Invisible Kid just as he destroys the components of Tharok's brain controlling Validus.