I feel like before I even start this I should say that I am a first time player lol
I have six and a half hours in my current save, and my only vehicle is my beloved seamoth. It has all of the depth upgrades, the perimeter defense, and the hull reinforcement. I just got the third depth module yesterday, so I decided to see if i could find anything interesting. I ended up roughly 2000 meters from the lifepod, with the Aurora being on my right side when I left the lifepod. I knew this was reaper territory, but I had yet to actually be attacked by one so I thought I would be fine.
At one point while I was looking around, the reaper got a lot louder but I still couldn't see it. Then something started pushing my seamoth, not attacking it but just shoving it. The second I stopped getting pushed I went and hid in a cave for the next few minutes lol. After deciding that it was probably a bone shark or something, I went back to looking around. I found what I'm pretty sure was the void, turned back around, and had just hopped out of my seamoth to grab a gel sack when all of a sudden the light from my seamoth went flying away. The reaper had grabbed my seamoth, while I wasn't in it, and was eating it!(which yes I knew could happen but I didn't even hear the reaper before it did this so I thought I was safe) It let go so I went to go get my seamoth and hopefully fix it enough to escape, but before I was anywhere close it grabbed it again and exploded it. And then it turned around to get me. Pretty sure the only thing that kept me from dying was the fact that I'm used to avoiding enemies in horror games instead of fighting them, so I just dodged it as best I could and then went by the 'if I can't see you you cant see me' rule as I swam away with my seaglide. It was at this point I realized that I was near the island with the alien building, so obviously the reaper was there, but I didn't know that from where I was underwater.
Made it back to my base and ended up just quitting to the home screen before restarting the game. I hadn't saved at all while I was playing today, so it put me back to where I started with my precious seamoth un-eaten. Maybe it's cheating but I really didn't want to lose all of the progress I had put into it lol. Then I promptly left the game again and decided I'd had enough subnautica for the day. Definitely learned my lesson this time.