To investigate the Tadpole Pens in Subnautica 2 , you need a mysterious keycode. It would've been handy if the keycode was located at the Tadpole Pens ruins, but unfortunately, it's in an entirely different location, so don't waste your breath searching the wrong area. To get the keycode, you must venture into deep, heated underwater caverns — be sure to mind your water and oxygen levels. Here's where to find the keycode needed to investigate the Tadpole Pens in Subnautica 2 . [ Ed. note : Before you dive in, be sure to open the character menu and enable all landmark signals . This will make it easier to spot the locations mentioned in this guide.] How to investigate the Tadpole Pens in Subnautica 2 Shortly after finding the Wander Blackbox and curing the Angel Comb, you should get a Noetic Advisor alert named " tadpole pens ." Listen to the alert to start the "Investigate the Tadpole Pens" mission.…