Gentleman Ghost

Gentleman Ghost is a supervillain from DC comics who varies between being a criminal who pretends to be a ghost or an actual spirit - in both forms he is a criminal and can perform a number of spectral abilities that make him tricky to combat (such as his ability to phase through solid matter): as well as being in the comics he has appeared in the DC animated universe as a minor villain in Justice League.

Infinite Crisis
In infinite crisis he attacked the city of metropolis and fought with all his defenders, especially Alan Scott which he left in a coma.

He later summoned an army of vengeful ghosts from his enemies and fought with Stargirl, however the girl managed to defeat him and foil his plan thanks to her immunity to ghostly attacks.

New 52
In the New 52 Reboot he is a thief instead of a ghost, he steals the Mortis Orb and used Hawkman to charge the orb.

When the orb regained its full power he creates a portal from which Julius Gates comes out and grabs him, forcing the latter to fight with him inside the portal.

He disappears along with Julius when the portal was closed by Hawkman.

Trivia

 * He is similiar in appearance and personality to the Paperinik antagonist Mr. Invisible.