help to ID this possible anti theft device

New member here... I just bought a 2004 Tundra after not having a truck for a few years and it feels great. I had a 2001 Tacoma that I got up to 270k miles without any issues before trading it in for something more carseat friendly. Hoping this will last as long.

Does anyone have info on this device? The previous owner wasn't sure but said the truck won't start without it. When I press the button, it turns red along with the exclamation point above the button. There aren't any numbers or words on it. I'm just hoping someone may have the same thing and give me a clue...
Thanks!

 

That's definitely not stock.

Have you tried starting and driving the truck without it near the truck?

 

Yeah, just kept it inside the house and won’t start

 

Does it open like the key fob? Maybe you can find something on the inside?

 

Look for a device under the dash or something with extra wires that looks out of place.