SOURCE

let speed=3;
let d=50;
let x;
let y;
let c=0
function setup(){
    createCanvas(600,600);
    x=width/2;
    y=height/2;
    noStroke(0)
    colorMode(HSB,360,100,100,1);
}
function draw(){
    c+=0.1;
    if(c>360){
        c=0
    }
     background(50,0);
    fill(random(360),50,100,1)
    if(mouseIsPressed==true){
        x=mouseX+random(-speed,speed);
        y=mouseY+random(-speed,speed);
          x=constrain(x,0,width);
        y=constrain(y,0,height);
        triangle(x-15,y-50,x+15,y-50,x,y-25);    
    }
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/1.1.9/p5.min.js"></script>