Splat (noun)

1. The sound of something soft and flat striking a surface.
2. A flat, spreading mass or stain of a liquid or soft substance.

Origin:

1860s, imitative.

Examples:

1. The tomato made a splat when it hit the ground.
2. She heard a splat and knew someone had thrown a water balloon.
3. There was a splat of mud on the car's windshield.
4. The paint made a splat on the wall.
5. The splat of the paint on the canvas was a sign of the artist's impulsive style.