Help making a script that makes something spawn when a player enters a room

I want to create a creature in my game that will slowly appear in a room if the player is in it for too long. If the player is in there for about 10 seconds then the creature will start to come through the roof and stare at the player. I’m not sure how I would do this so any help is appreciated!

You could detect the room using regions. While the player is detected in it, it’ll launch a timer. Once 10 seconds pass do anything you need. Or you might use the distance from one point to the player and see if he’s close enough. Though the detection radius is a circle.

You can make the timer work by adding a 1 once a second passes.
Or what I’d like to do:

timer += wait(seconds)

It’ll both wait needed amount of time and add the number to the ‘timer’ variable.