While Zack Johnson can be considered a villain to Leonard, he was actually a pretty decent guy deep down. Though, he had the intelligence of a stump.

The reason he was considered an antagonist for Leonard is the fact that he dated Penny. The two of them really weren’t that bad of match. She definitely had the opportunity to be the smart one, lol.

He actually shows up near the end of the series with a new wife and wealth. Turns out he was shooting blanks and he wanted Leonard to donate his DNA so his wife could have a child and a genius one too. Talk about awkward and ironic.