How do I get past the Labion Root Monster in Space Quest II?
I agree with the other posters that there is no special trick, but I recall from the Apple IIGS version that tapping the arrow key once would start you walking in that direction and tapping it again would stop you immediately. I employed a double-tap keyboard approach to navigate the root monster (or any other tight space) in which I would give two immediate taps (taptap) and move one "pixel unit" in some direction.
If you're playing an emulated/Flash version and have to use a mouse I would imagine the difficulty would go up.
This is the one in Space Quest II, right?
There's no clever trick to getting past it; navigate between its roots without stepping on one.