ok nice... thank you ! i did even more ! ;) there is sound with it... and if you are far you can't hear it :) (a friend helped me)
1st Script : Display the lightning randomly
var randomFrames = Math.floor(Math.random() * 241) + 60;
this.wait(randomFrames);
2nd Script : Allows you to hear the thunder from a distance; the closer you get, the louder the sound becomes
var playerX = $gamePlayer.x;
var playerY = $gamePlayer.y;
var eventX = $gameMap.event(75).x;
var eventY = $gameMap.event(75).y;
var distance = $gameMap.distance(playerX, playerY, eventX, eventY);
var maxDistance = 30; // La distance maximale à partir de laquelle le volume sera réduit à zéro
var volume = 90 - (distance * (90 / maxDistance));
if (volume > 0) {
AudioManager.playSe({ name: 'thunder9', volume: volume, pitch: 100, pan: 0 });
}