As others mentioned, it is an achievement from Half Life episode 2. Player has to carry a garden gnome to the end of the game. Which is not too bad, minus the extensive driving sections (sometimes under fire) where the gnome is bouncing around the vehicle.
It is a fun feather in your cap, but definitely not suitable for a first run through of the game.
Ah, thank you. I’ll admit to never having played it.
A small charge of C4 works wonders. Just be sure to lay your head over in the passenger seat before detonation.
I carry a small hatchet in the trunk of my car with the spare tire just for this reason.