I will hazard a guess this is c. 1920s-'30s. The galalith sautoir was designed to resemble ivory, and mission accomplished! It measures 2" long x 1 1/4" across. Celluloid chain is about 30" long. Loop holding pendant to chain is obviously a later-day addition, and I have no idea if these two pieces were originally wed or if they met up later, but they are indeed complementary.
I do not know the significance of the figural. Hoping it does not prefigure Death. At any rate, this is a splendid old necklace in excellent condition with the exception of a bit of wear to the BACK of the pendant.