That’s not a very easy question to answer. I’ve never seen one myself so I can’t say for sure if they exist or not. I’ve had family members say they’ve seen one and I’m not about to call them liars but again, since I have no eyewitness experience, I’m unsure.
I’ve seen all kinds of documentaries that ‘show’ images caught on video or in pictures and all kinds of paranormal sounds and activities but I don’t know if that is entirely conclusive. I’d like to believe they exist and I’d really like to see one someday to confirm my suspicions but for now, I’d have to say it all comes down to someone’s individual perceptions and/or beliefs and/or experiences if they are real or not.