I know this is really old but you missed the point, I'm afraid. Nettling imp is basically a modified royal assassin that combos with a real royal assassin. On its own, it destroys any tapped creature. So having a solo imp lets you take out any creature that is not indestructible and has a tapping ability. Forcing a tapped creature to attack (which it can't do because its already tapped) then destroys it. Obviously this also combos with Icy Manipulator. About the only creature immune back in the day was Serra Angel because this was before they came up with the word "vigilance" to describe her ability and gave it to other creatures - one of the reasons the Angel was in so many decks in the early 90s.