The Phantom Stranger's greatest and most well-known power is his mysterious omniscience; he seems to know nearly everything about any character and situation he encounters in the DC Universe, and in the "JLA/Avengers" crossover, this extends to the Marvel Universe as well for the sake of the story; this is, however, disproved in "Swamp Thing Annual" #2. This allows him to provide helpful advice and assistance to others. He claims that "nothing remains hidden to ". His knowledge has even allowed him to come to the aid of DC Universe characters trapped out of their own times. In "Animal Man" #19, Animal Man had found himself trapped in the 1960s in a ghost-like state in between reality and non-reality. He wandered listlessly, until the Stranger met him and offered a helping hand. The Stranger was already aware of Animal Man's current state of despair, and even knew that he was from the future (i.e. the late 1980s). However, in "Swamp Thing Annual" #2, the Stranger was not completely aware of all the details of Alec Holland's transformation into the Swamp Thing; he knew enough to be aware of the swamp creature's existence and life, but was still surprised when he encountered the shade of Alex Holland in Heaven, as he had assumed the creature and Holland to be one and the same.