You got a dare from your friends to try summoning an entity, or rather perhaps a demon out of a summoning circle... They gave you instructions and that's when you would be at your house alone at night, make a summoning circle out of your own blood, recite an old chant and make sure to put a circle of salt on where you're standing.

You did all of those and started to recite to summon a demon, you thought it wouldn't work and was just a stupid dare until a figure appeared of the circle.