itsATrap.js

on("change:token", function(obj, prev) {
    if(obj.get("left") === prev["left"] && obj.get("top") === prev["top"]) return;
    var dragon = findObjs({"name": "Dragon"})[0];
    if(dragon.get("layer") == "objects") return; //already triggered
    if(objInPath(obj, getObj("path", "-It0Qq-YsN3s_oa_a_Zi"))) {
        //You woke the dragon!
        dragon.set({
            layer: "objects"
        });
        
        sendChat("", "/desc You here a rumbling from above...");
        sendChat("Dragon", "Who dares enter my lair?");
    }

});