Respect the Red Right Hand
Dark Danny = (do the films count?). He was just unnerving, not to mention totally fucking badass
Pariah Dark = He wasn´t all that interesting as a character, but damn was he strong
Ghost Writer = I just loved him, especially since he was felled by not knowing a word that rhymed with orange
I had to double read the topic title to make sure it said "Danny Phantom" Haha.
I really liked Dark Danny and Nocturne.
I really wish they used Dark Danny again, when I was little and I finished watching Ultimate Enemy I remember being kind of.... traumatized for a few minutes. Not even joking, I was just sitting still looking at the screen and shaking a little bit after it ended. For a little cartoon to have an effect like that to me (I was like, 10, so chill) it must have hit hard, so when they hinted at a return I was a bit scared but I wanted more, heh.
I really liked Frightmare. Even though it gets some flack in the community and its part of that "infamous" 3rd season, I thought it was a great episode with the way things were paced, and extremely cute. Even though he was such an unrealistic ghost, he certainly felt powerful and I loved that about him.
I liked Frightmare, Dark Danny, and the Ghost Writer. Now I feel so unoriginal. :P
I liked Frightmare because I thought his plot was good and because I loved his character design.
I liked Dark Danny because he was just so evil. I mean I can't believe they actually had a villain like that in this show. But it was awesome!
I liked the Ghost Writer because I thought he was kind of funny and I liked the episode he was in.
I miss that show. It's where I got my username.

There are a few ghosts/characters that only appeared in one episode. Out of these characters that appeared only once which are your top three.