BSODOD is a Forge mod that intends to make Minecraft a bit more challenging. It does so by making you blue screen (i.e. making your entire computer crash) when you die in the game.
The mod uses undocumented Native API methods to raise an error in a critical system process and instructs the system to shutdown on said error, meaning blue screen. It does not damage your system to create the blue screen.
That being said,
I do my best to prevent that from happening, however if you believe you have encountered a bug in the mod, feel free to open an issue. Try to be as descriptive about it as possible. What exactly happened in your game the seconds before blue screening? Retrace your steps.
You can configure the mod in .minecraft/config/bsodod-client.toml.
The URL that opens before you blue screen. Rick Astley's Never Gonna Give You Up by default. Set to 'none' to disable.
The delay in seconds before you blue screen after your death.
Whether or not the mod is defused. If true, the blue screen will be replaced by a log to the console.