J'onn J'onzz, AKA Martian manhunter, has the ability to go intangible.
My question being, why does he not use this ability full-time whilst in battle?
Are there any limitations to his intangibility, or is the answer out-of-universe?
Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.Sign up to join this community
There aren't many limits. The main one is that he's doing this "manually". Density shifting is a conscious action. If he's distracted, or surprised, it won't work and/or fail. And he gets distracted by fire, electricity, plasma, those kind of things (these all generate heat).
For example, in the Young Justice cartoon, season two, during a battle aboard an underwater Reach ship (episode 10, Before the Dawn), Miss Martian tries to phase through a door. The Black Beetle notices her and shifts the density of the door, surprising her, and rendering her unconscious (and stuck halfway through the door). In a later episode there was a risk that fire from Deathstroke's grenades would prevent her from escaping via density shifting.
As for the Martian Manhunter himself, I don't remember any specific examples, unfortunately, but I'm sure fire would interfere. In the Justice League: Doom movie, he was painfully "shocked" and thrown off to the ground by King's handheld plasma emitter (handheld plasma something, I can't remember exactly). In the same movie, he couldn't use intangibility to escape the fire set on him.