So there's already some kind of stealth system. There's the "net" weapon. There's the grabby feet to latch onto things.

How about a deploy able lure? Maybe one on a string, one free floating? Maybe it could trigger that late-level tracking system? Maybe split them further into acting/looking like an enemy or food.

Another could be a kind of "Ink Cloud" that can help you create some confusion before you strike, or help you escape a bad situation. I could create a temporary zone of "Stealth cover". There could be a structural version too, that drains energy while in use that deploys a stealth area based on the level you're in.

My last idea would be a decoy. Shoot it out, and it takes the form of your core zooid with maybe a structural node attached and it wiggles around like a hurt little guy. Maybe upgraded it could cause poison or paralysis.