|obj||The object or instance to check for the existence of.|
This function can be used in two ways depending on what you wish
to check. You can give it an object_index to check for, in which
case this function will return true if any active
instances of the specified object exist in the current room, or you
can also supply it with an instance id, in which case this function
will return true if that specific instance exists and is
active in the current room.
Please note that this function does not take into account those instances that have been deactivated using the instance_deactivate functions.
score += 200;
The above code checks to see if any instances of the object "obj_Enemy" exist and if not it adds to the variable "score" and changes room.