King Saurus the third (or III)(キングザウルス三世) is an Ultra Kaiju - meaning he is a Kaiju (monster) from the Ultraman series of TV shows. In particular, King Saurus is first seen in the 1971 series "Return of Ultraman" (帰ってきたウルトラマン).

King Zaurus's full name literally translates to "Ancient monster meteor kick zaurus King III" (古代怪獣キングザウルス三世). He first appeared in Episode 4 of Return of Ultraman, dated 1971/4/23.

There have been many reissues of this toy over the years. This first release came out in 1989, followed by 1991, 1995 and 1998, Reisses can be marked by different colored vinyl. The original is in grey, followed by a purple-ish release.

As a special bonus...

I tried to find video of King Saurus III in action, but instead i came across this.

Daicon Film's Return of Ultraman, from 1983, an Ultraman parody film written/directed/starring Hidaeki Anno (you know, that Evangelion guy). It's pure otaku goodness. Long, but worth it.