system
A chat on 4chan
human
Mammon/Maymon if you're fine with invoking 'darker' spirits. And you're going to have to work your ass off.
gpt
This works.
human
Mammon is cool. You'll need to start meditating daily and invoking a lot in order to communicate effectively. Some people will start with pendulums for yes and no answers. It also helps having incense and a glass of water nearby for any sort of summoning. If you're sincere and work hard then you will receive help. It doesn't go unnoticed.

Magic is a manifestation of your will. As for a 'spell,' this is what another spirit told me. 
'See what you want to happen. Speak it. Will it. Know that it has taken place.'