> tag remains radio silent unless it sees a specific 32 bit code from the reader.

So you could spray sticky rfid chips into an enemy’s hair, undetectable when scanned, and later on you could send the correct signal to identify enemies in the room. Later their hair would be trimmed, leaving no trace.

Aside from the cool privacy aspect, it seems like it would be cool to:

- Attach to insects to later use a detector to find their homes.

- Coat it and eat it to track your digestion.

- Use it in a miniature tornado model or wind tunnel along with a radio spectrograph to have cool visualizations.

- Embed in paintings, 3D models, clothing labels, and more to verify authenticity, get serial numbers, or track inventory.

- Drop a trail of them behind you so others can follow the trail and find you!