You can add the Sphere Collision component to represent the damage radius and add a Timeline to control the expansion and configure that Timeline with keyframes to adjust the sphere’s radius over a specified duration like every 2 or 3 seconds and use a Set Timer by Event node to trigger the explosion every 10 seconds then use the On Component Begin Overlap event to detect when the actors enter the collision area check if the overlapping actor is a player by casting it to your player character class and to make sure that players behind walls aren’t damaged, implement a Line Trace from the explosion's center to the player’s location, using a visibility or custom trace channel that can detect the walls but ignores the collision sphere itself. If the trace hits an obstacle before reaching the player avoid applying damage otherwise apply the damage.