I was simply building and found some script callled "inFECtion" I opened to find there was a script that was simply a virus and have no idea how to remove it. I NEVER used any free models in my game. I have no idea what to do ;-;
Try resetting the place to the version from before you noticed the "virus".
Go the "Develop" page on ROBLOX
Access the PLACE configuration by clicking on the gearbox icon beside your place
Click on the "Version History" tab
Find the correct version by looking for the date in which you remember the virus wasn't there.
This isn't an answer so i'm sorry but you can easily get a Vaccine script or virus remover plugin to easily get rid of em.