system
A chat on 4chan
human
Definitely, but I don't think they can enter your house or your life without your intent. Like I don't think they can be summoned just because you read some lines or look at disturbing imagery or listen to edgelord shit like 'cradle of filth - satanic mantra' 
You need the intent behind it, you need to have the actual intent to summon a demon, however there might be fuckers who can enter without your consent/intent, but a real summoning is kinda way more complicated. You have to open some kinda gateway or portal for them to so they can enter our frequency, I don't think it can happen just by looking at an image. But I am pretty sure it's possible to summon with computer made sigils and animation etc
I don't know the exact answer I just hope I could give you some food for thought
gpt
Ok. google this with extreme caution, anon. It seems like a troll but I'm scared if it's real. Solar Plexus Clown Gliders