Sandu, a mystical carny, was already gifted with extra sensory powers before Loki endowed him with mental powers that were over one thousand times more formidable.
Sandu was created by Stan Lee, Larry Lieber and Joe Sinnott in 1963 and first appeared in Journey Into Mystery # 91.
With Loki being watched in Asgard by Odin and the rest of the Asgardian Gods, he needed to find a way to gain vengeance on his mortal enemy Thor. To do this he would have to use an agent on Earth to do the job for him. Not even Loki himself could defeat Thor so he increased the mental powers of Sandu over one thousand times its natural power. This would make him a more than formidable foe for Thor.
Thor, as Donald Blake, and Jane Foster visited the carnival that Sandu performed at but were unaware of the danger that was present. Sandu discovered the powers that were granted to him and immediately had sinister plans; thus fitting right into Loki's scheme. While Sandu began a thieving crime spree, Thor desperately tried to figure out who was responsible.
When Sandu became satisfied with the power that he had attained, he came out of hiding and fought Thor. Sandu quickly defeated Thor, chaining him and placing a building on top of him. Odin then sent the Valkyries to give Thor his belt of strength which allowed him to tunnel out and continue the fight. Through advice from Loki, Sandu managed to send Thor's hammer to another dimension but he became frustrated when he could not control it or even lift it. This allowed Thor to regain his hammer and defeat Sandu.