From his team-up with Dare Devil. "Thank God for Stilt-Man!"
Issue 4 was funny from start to finish, from Otto learning with displeasure that Peter is not a doctor to Ghost Peter snarking about Otto's age.
Also in Issue 4 when Modell and Jackson check up on Otto's mad science experiment, his Robot Buddy — a reprogrammed Living Brain — asks if they want tasty beverages which they decline, a few pages later:
The Living Brain: Tastier beverage?
The Living Brain: Added sugar, humans like sugar.
Issue 6. Otto still laughs like a good old-fashioned supervillain, which creeps out Peter's coworkers.