If a token is put in the Cramped Bunker, the object being used to represent the token is what must get in the bunker. You’re not allowed to change what that object is once Cramped Bunker appears. For example, if you’re using a Zombie token card to represent an Angel token (weird, but sure), you can’t suddenly decide you’d rather use a penny. If you create a new Angel token, you can use a penny.