I was playing hardcore mode and I was mining stone then a silverfish spawned
There was no structure to be got a chance of spawning infested stone which I accidentally broke and silverfish spawned
https://drive.google.com/file/d/1QVGi5NYHs0GKfd75wx6tvE7uiv1TnlTJ/view?usp=drivesdk
Check the glitch in this 👆 link
Infested stones can be produce silverfish spawn naturally when mining, That is an intentional behavior.