Not Fantastic
Issue 8 of Fantastic Four pits the FF against the Puppet Master, a typical comic book villain (hasn't every superhero fought some guy who called himself 'the puppet master' at some time in his/her career) who uses little puppets (fashioned from radioactive clay no less) to control the actions of people of their likeness.
The story reads like a typical Silver Age story from one of the sci-fi/fantasy anthologies like Journey Into Mystery, with the members of the Fantastic Four as incidental characters in the story and the Puppet Master as the actual protagonist. This is particularly apparent when we see the Puppet Master's downfall, which comes about totally without any intervention by the Four.
The story does introduce Alicia, the character that will become the love interest for The Thing, so fans of the Thing will probably want to check it out - but others can probably safely skip this one.