Subject: Trying to find the name of a toy, please help.

I'm trying to recall what an old toy was called.
It was a brightly colored (like neon green) almost submarine shaped plastic toy that had a string running through the top part. On the bottom of it was a detachable black plastic hook (sorta shaped like a W in that it had a hook on the left and the right), that was used for picking up objects such as the "bucky ball like" pink or green spheres that were included with it. (These could be split apart and you could mix up colors, or place action figures inside )

But the toy worked by tying part of the string spool (a rectangualar black spool.) on to a door knob or other object. Then you back away to reduce the slack on the string and to race the "Inster proper toy name here" off the ground. The "sub thing" was weighted, so that when you lifted the string higher than the door knob, it would zoom towards the door knob, or if you held it lower it would zoom back to you., and you could make it swoop down and pick up the bucky ball like things.

Does anyone have any idea what I'm talking about? I mainly need the name so that I can know what I'm looking for.