Zachary Quinto suffered a nasty burn on the set of Star Trek Into Darkness while filming a fiery volcano scene.

The star, who plays Mr. Spock in the hit sci-fi franchise, put on a protective heat suit for the shoot before thrashing around in the hot magma, but unaware a portion of his skin was still exposed, Quinto ended up with a large welt on the back of his neck.

The 35 year old tells the National Enquirer, "My neck skin got caught in between the helmet (and my shoulder). I didn't know how serious it was. I didn't know what was happening. (Director J.J. Abrams told me,) 'It looked like there was a caterpillar on your neck!'"