The Mind Controlling Device/Lie about it.
From Create Your Own Story
You: "It's not a watch. The doctor gave it to me and told me I'd have to wear it for a while to monitor my blood pressure or something."
The others seem to buy it. Good. You don't really know why you lied about it, as you trust these people, but it seemed like the right thing to do. For now, noone should know what the watch really is. Especially as it came with a warning. You don't know what these eviiiil Sylex are and you don't really want to find out. The bus will be driving for another 15 minutes before reaching the school. As you talk with your friends, you think about what you want to do with those 15 minutes.
