A man jealous that he won't get the credit for discovering the missing link takes some dynamite to blow it up, but all he succeeds in doing is releasing it and it attacks him.
A rich man becomes annoyed when he sees a junk dealer's horse and wagon move in next to him. The end of the story reveals that the neighbor is an earlier version of himself. His success had poisoned the compassion that he used to feel for people, but now that he has faced what he has become, he resolves to turn over a new leaf.
A mind reader encounters a disguised alien who comes from a planet rich with gold and diamonds and he decides to blackmail treasure out of him or he'll expose him, however, the aliens easily apprehend him because they all read minds.