Fantastic Four: World's Greatest Heroes 1.10

De-Mole-ition

New York City is invaded by a gigantic creature from undergound. The Fantastic Four go looking, after immobilizing the creature, and discover that the Mole Man lured it above ground. He didn't want it underground when its eggs hatched.

The Mole Man captures the Fantastic Four but the Invisible Woman escapes. She returns to the surface and helps the gigantic creature find the egg that the Mole Man placed in the Baxter Building. She then returns with the creature. She helps to free her teammates and together they prevent the Mole Man's plan from succeeding.

Fantastic Four: World's Greatest Heroes 1.09

World's Tiniest Heroes

Johnny brings a neighbor's dog into Reed's lab while he performing an experiment that involves shrinking technology. The dog starts running around the lab knocking things over. The next day the team wakes to find themselves smaller. They continue to shrink as they try to make their way to the lab.

HERBIE, the Baxter Building's computer, doesn't recognize the team in their reduced state. It concludes that they must be vermin and attempts to dispose of them. Dr. Hank Pym (aka Ant-Man) shows up and lends the team a hand before they shrink out of existence or get killed by HERBIE.

Fantastic Four: World's Greatest Heroes 1.07

Hard Knocks

Reed is attempting to help his friend, Bruce Banner, when he unexpectedly causes him to transform into the Hulk. Reed is knocked unconscious. Reed's teammates, unaware that Bruce Banner is the Hulk, start to fight with the Hulk. Reed clues them in once he recovers consciousness.

The Baxter Building is infiltrated by agents of Home Base, led by Agent Pratt. The forces fo Home Base attempt to capture the Fantastic Four but in the end settle for their original target, the Hulk, who by then has transformed back into Bruce Banner. The Fantastic Four go after Agent Pratt and the Hulk. They catch up to them in the desert.

Fantastic Four: World's Greatest Heroes 1.04

Doomed

Dr. Doom injects Reed Richards with a serum that allows him to switch bodies with Richards. Doom proceeds to do what he can, while in Mr. Fantastic's body, to wreck havoc in the Bazter Building. Reed wakes up and finds himself trapped in Doom's body within a force field created by Doom within Doom's headquarters.

Mr. Fantastic, still trapped in Doom's body, escapes from Doom's lair and heads to the Baxter Building. His former teammates don't recognize him and attack him on sight/ Sue figures out what is up and teams up with Reed, while he is still trapped in Doom's body, and helps him reverse the process and defeat Doom.