(I was thinking of that collar that the Slitheens wear in Doctor Who, but I didn't feel like searching for it, so I just used a Mini Mushroom.)
Replaces the Spy's Invis-Watch.
Instead of turning invisible, the player shrinks down to about as tall as the Soldier's boot.
Players can still see the Spy, but they would have to look down.
Being small allows the Spy to bypass Sentries, run under tables, etc.
If a shrunk Spy gets stepped on by an enemy, or if an enemy jumps/lands on them, it's an instant-kill.
When small, the player's voice gets really high-pitched and quiet to other players.
It's also very hard to hit a small Spy, making it good for getaways. (However, when you're small, you take twice as much damage. I forgot to add that in the image.)
Unlike other cloaking tools, a shrunk Spy CAN fire his gun; It just deals 90% less damage to full-size players. (The Knife deals no damage, because it wouldn't cut through boots. Plus you would probably die if you got close enough to stab. xD)
The gun and knife deal regular damage to an enemy shrunk Spy.
The Compression Field doesn't have a recharge mechanism like other Invis-Watches; You can stay small as long as you want. However, you can only shrink 5 times. Resupply cabinets refill your shrink count, and large ammo crates grant an additional shrink if one has been used.
It takes 20% longer to shrink and grow than it takes to cloak and uncloak with the default Invis-Watch.