Make an enemy appear and then disappear at random?

I am making a scary game and want to make the enemy appear in front of the player then disappear a couple seconds after. Can anyone please help? I just started to make games so i am a scripting noob. Help would be greatly appreciated!

I am working on a scary game as well. I placed a box with a box collider and it functions as a trigger. Once the player hits the trigger (Search: ontriggerenter) you can unhide the enemy. With “yield WaitForSeconds(3)” it disappears after 3 seconds.