What is/was this toy?

Factual Questions
1

Waaaaay back in the late 60s/early 70s, there was a toy (not really high on the entertainment value) that consisted of a silver/'mirrored" half-sphere on a small pedestal, with a small rubber ball dependant from a wire inside the half-sphere. The whole point of this toy was tap the ball so it would swing back-and-forth or to-and-fro, and watch the reflection change size (Oooooooooooooh!! Pretty!). As I said, not very high on the entertainment value unless you were stoned [it was the 60s/70s] or a small child [me back then].

What was the general name of this toy (brand name asopposed to cheap copycats & knock-offs, like the Rubik’s Cube and that ilk)?

Anyone know if/where I can still get one?

2

I forget what they’re called, but I remember buying one at Spencer’s Gifts back in 1973. If anyone still sells those things, it would be Spencer’s. (Are they still in business?)

3

They are still in business, but they ditched the “darkened section in the back of the store with all the adult material lit with the fluorescent tubes and lava lamps” a long time ago. (All the adult material is scattered throughout the whole store, btw.)

4

Desperation last chance ‘bump’ for the name of this toy: it’s kinda hard to google ‘silvery swingy reflective thingy’ with any sort of result.