FANTASTIC FOUR (1961) #56

Ulysses Klaw returns for revenge! Following his defeat in Wakanda at the hands of the FF, Klaw attacks the Baxter Balding armed with sonic super powers! While attempting to escape from the Hidden Land, the Inhumans have an unfortunate accident. This issue opens on Reed and Ben examining sub-space (AKA the Negative Zone), with Sue worrying about what the dangers could be. As they continue studying it, their laboratory is sealed by an unbreakable wall of solidified sub-sonic waves by Klaw, whom they faced alongside the Black Panther several issues ago. Unfortunately, he has used his sonic converter to turn himself into solidified sound.…