I am very, very new to GMS in general. I've completed the My First Game - Code Tutorial and now I am diving into DnD. I wanted to experiment a bit on my own so I can find my (massive) short comings and, thus, see what GMS2 concepts I need to nail down. Thus far, I had no issue getting my player instance to move about using the standard WASD keys. Yay, me! Now I've placed an instance from obj_wall with the intent of making the player instance stop moving when it collides with the wall instance. So far, I am failing at this simple task. Boo, me. With the player object (obj_player) selected and open in the work space, I go to Add Event and select Collision>obj_wall. But now I don't know what DnD object to drag into the Code area to cause the player instance to stop when a collision is detected between the wall and player. Any help here would be appreciated. As a side note: both spr_player and spr_wall have basic rectangular collision masks set with collision set to middle center. Also, I did drop in a Restart Room (when I couldn't get anything else to work) and that works. So, it appears GMS2 is detecting when the player instance collides with the wall instance. I just don't know what to drag into the code area to cause the player instance to just stop. Sorry for being so dense with this.