Christopher Markus, one of the writers on Avengers: Infinity War, discuses filming the early introduction of Smart Hulk in the film but explaining it ultimately didn't work. Markus is a prolific MCU creative, having co-written both Infinity War and Avengers: Endgame with Stephen McFeely. The two also wrote all three Captain America movies, as well as Thor: The Dark World. Due to the number of Marvel films Markus and McFeely have worked on, the two have a good handle on the characters of the MCU and what works for them. This includes Mark Ruffalo's Bruce Banner/Hulk.

In the past, Markus and McFeely have discussed the introduction of Smart Hulk, a version of the character that's a hybrid of Hulk and Bruce Banner. Originally intended to appear during Avengers: Infinity War's Wakanda Battle scene, Smart Hulk's transformation was instead saved for Avengers: Endgame. The writers have revealed a host of things contributed to the decision, explaining it happened at "the wrong moment" and saying it was "this moment of victory while we were headed toward defeat." Markus and McFeely have also spoken about all of the surviving characters needing a change between Infinity War and Endgame, which contributed to their decision to wait on Smart Hulk.

Related: Avengers: Endgame Script Reveals Smart Hulk Is a Science Celebrity

During the Wakanda Battle, and specifically his fight with Cull Obsidian, Bruce instead wears the Hulkbuster armor. This allows him to assist the other Avengers without transforming. During a watch party hosted by ComicBook, Markus again discussed cutting Smart Hulk's transformation from Avengers: Infinity War. In particular, he spoke about filming the scene, saying "Ruffalo was genius, arguing with himself," before allowing it "didn't work for beans."

Though Avengers: Endgame provided closure for Hulk, his time in the MCU may not be over yet. Many fans have assumed Ruffalo will reprise his role in Disney+'s upcoming She-Hulk series. This is partly because She-Hulk is expected to follow the comics origin story, which shows Jennifer Walters becoming She-Hulk due to a blood transfusion from her cousin Bruce. However, Ruffalo recently revealed there's discussion of him appearing, but a deal hasn't been finalized. If it does come to fruition, it would be Ruffalo's first turn as the Hulk on the small screen.

The writers of Avengers: Infinity War have discussed why they cut Smart Hulk from the movie in the past. However, it's interesting to hear the added details from filming the scene, including about Ruffalo's performance. Though some fans were disappointed the Hulk was MIA during Avengers: Infinity War, Smart Hulk's introduction in Avengers: Endgame is one of the movie's funniest moments. Despite differing opinions, Markus and McFeely probably made the right call in putting off Smart Hulk's introduction.

More: Smart Hulk Was Supposed To Be Marvel's Last Remaining Hero In Endgame

Source: ComicBook/Christopher Markus