GUI Pop-Up On Cube Collision

How would I make a GUI pop-up when my player collides with a cube? I want the GUI to be like the dialogue in an RPG game and allow you to click to continue reading the dialogue, and I want the player to be frozen until the dialogue is finished and the GUI goes away.

You could make a boolean (variable which is either true/false) called isColliding or something. Then in your player control script, you could have something like

if( !isColliding ) {
  // move player according to input

then do something like this for the dialog

void OnGUI() {
  if( isColliding ) {
     if (GUI.Button(new Rect(10, 10, 100, 100), "Watch where you're going!") {
       isColliding = false;

You’d have to remember to set the isColliding variable to false in some Start() function, and set it to be true when a collision is entered. Haven’t tested this out, this is all off the top of my head.