This vessel contained liquid, and was one of several plastic Star Trek dishes produced by Deka. In 1979, they produced some for The Motion Picture.
From what I can find, Deka produced plastic dishes from the 1960s through the 1980s, including many for movies, TV shows, and cartoons. In addition to Star Trek dishes, they made dishes for Star Wars, Smurfs, Garfield, Pac Man, Care Bears, ET, Popeye, Go Bots, and Cracker Jack, as well as many non-licensed items with decorations for holidays or other general decorations. I haven't been able to find any sort of history of the company, but it seems they're no longer in business.
|The date is next to the handle.|
|The U.S.S. Enterprise and a Klingon or|
|Good thing this guy is labeled "Captain Kirk,"|
because we might not be able to tell otherwise.
|Made in the U.S.A.|