As Bruce Banner/The Hulk in "The Avengers," Mark Ruffalo smashed his way through any obstacle he met. But in his latest film, "Now You See Me," Ruffalo was much more vulnerable -- and breakable.

In "Now You See Me," out Friday (May 31), Ruffalo plays Dylan Rhodes, an FBI agent trying to stop the incredible crime spree perpetrated by a group of magicians played by Jesse Eisenberg, Woody Harrelson, Isla Fisher and Dave Franco. In one intense fight scene, Rhodes is totally outmatched by Franco's character, Jack Wilder, an expert pickpocket who has also mastered the art of card throwing.

Franco wanted to make sure the flying cards looked convincing as a weapon. "We started practicing card throwing from day one," he said. He surprised himself by actually getting very good at it. "It's kind of embarrassing how good I am at throwing cards, where I can actually cut a banana in half now."

When it came to shooting the fight scene, both Ruffalo and Franco were raring to go. "We were taught the choreography for it but I think the design was that the stuntmen were going to do that scene," Ruffalo said. "And we just said, 'No way, man -- we're doing this.' And it's a great fight scene."

But Franco's card-throwing skills made the scene a bit too genuine for his castmate. "I cut up Mark Ruffalo's face real good," he said. "He was not happy with me."

And that was just one of Ruffalo's myriad of injuries he suffered from that sequence; he nearly dislocated his shoulder when Franco threw him up against a refrigerator. "I think we were both a little excited, and he's really a strong kid, and he really threw me," Ruffalo recalled. "And I went, 'Oh my god, please, young man, you're dealing with an old man.' "

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Franco admitted to being a tad overzealous while shooting the scene. "It was bad. I messed up," he said. "Your adrenaline's rushing, and I threw him a little too hard one time, and he hurt his shoulder, and so for the next hour or two it got a little real. I think he was getting back at me a little bit. And, you know, even though it's a fake fight, you're wrestling, you're rolling around, you're getting bruised up. But by the end of the day, we had a beer, we're all good."

While shooting another part of the sequence, Ruffalo had to deal with the dangers of matzo. "I'm chasing after [Franco], we were going through a matzo factory. And there were these baskets on conveyors that the workmen were filling with matzo, that were taking it through the factory." Ruffalo was supposed to hit one of the baskets and then keep going, but that's not exactly how it happened. "I'm running, I bang into it, and it just goes 'Boom!' and hits me right in the forehead. And down I go. And I looked down -- I'm just covered with blood."

It was just a temporary setback for the actor though; four stitches later he was back on set, ready to continue shooting. And though it wasn't scripted that way, Ruffalo's head-bang made it into the finished film. "If you look closely," he said, "you'll see me [run] and then fall."