Mark chooses April Fool's Day to ask Callie to take their relationship to the next level, but his romantic gesture is threatened when Callie's vengeful ex-boyfriend returns to win her back. Meanwhile, Leonard tries desperately to redeem a winning lottery ticket as Randall attempts to cut himself in on the prize.
When the country's biggest pop star ("Lady Hoo-Ha") goes zombie, millions of her devoted fans follow suit. When Mark befriends one of the new zombies, Randall is forced to deal with his jealousy issues.
Mark becomes a masked crimefighter after he's bitten by a rabid Bat-Boy. With the help of his loyal sidekick, Koala Man, Mark wages war against New York's criminals and their catlike leader.
With the big company intramural football game around the corner, everyone starts getting nervous about the lineup -- Mark is a wonderful team player, but a terrible actual player. When Randall demonstrates the power of his recently replaced arm, he is given a job at the D.O.I. as the team's ringer.