I want to paint my walls black and splatter neon colors but my mom wont let me. so instead we agreed i can sponge my walls in different neon colors. would this look good or did i agree to a ugly room?

Properly done it could be awesome.

use a white base colour on the wall and allow it to dry completely.

Mix your neon colours with faux finishing compound and a bit of water and pour them into flat containers, I like paint trays, but you could use margarine tubs or plastic plates.

You will need help doing this and I recommend you practice on a scrap of drywall to be sure of the look.

Use a damp sponge in each colour, dab it in the paint and dab it off on a paper towel. Start pouncing the paint onto the wall. not too much of each colour at first, remember you can always add more, it's tough to take it away.

Work carefully into your corners and small spaces until yo have the effect you like.

Then just let it dry. If you still want the black in your room, add pillows, wall art (frames in black) and other accessories in black. You might even want to consider black furniture.