It looks like a mesh with its face normals flipped.
If anyone is wondering how to flip the normals on a mesh, open Blender and select any mesh. Go into edit mode, select all faces, and search for “flip” to flip all face normals. In Blender it won’t look like it does anything, but once the mesh is imported into Studio your mesh will look different.
If for some reason this happens to you when you didn’t flip the face normals, you might have accidentally scaled your mesh by -1, similar to OP.
Did something new for practice. I’m not that great at building so I tried to do something new. Pretty happy with how it turned out.
Survivalist
It’s really good and Smooth Not your Average Roblox animations and Model I love it Keep up all the Good Work!
We are currently making the MOST REALISTIC game of Roblox with our team and we are very ambitious! 
In-game images will be shared soon!
Time to share: 20.00 
We recommend that you do not miss it! 
What time zone? Is it GMT? GMT +1, etc, please give more information.
Gmt+3
Thanks for the question!
I’ve been working on multiple projects, some big, some small and right now I’m working on a game called SNS [Sunday Night Singin’] And its a big open world FNF game. Heres a sneak peak of some of the new characters that’s going to be in the Story mode!
Hope you all enjoy it when it comes out!
So… summer break and pause of homeschooling was getting us a lil bit more power to continue working on @TinoH444 s game Stairways to Heaven
Finally… we added the U.F.O.s to the game and a planet earth you can only reach by flying there… staircase is high enough. And a leaderboard that is tracking what altitude players reached.
I love a good seamanship. This is a really nice collection of models… all bey your own? thanks for sharing!
MORE GENESIS THINGS.
Schools’ starting again within a few days and that makes me mad because I have less time to play games and procrastinate working on this project.
Anyway, very early pre alpha development game teaser whilst i avoid scripting the enemies (the idea scares me)
(note from the future - this game is in limbo until ai stops being so difficult to make, as is the fate for many of my other projects)
Space X? Rocket Lab? More like SPACE LAB!
In all seriousness, nice.
I feel like that room is empty maybe add a bookshelf
Some progress on my museum
This is beautiful. This sets the bar pretty high for all the other modelers out there.
Reminds me of Burnout Paradise! Awesome!