To put it simply, this short movie was about an black ball-like creature, I will call it Kuro, gets eaten by big monster, again and again.
At first, Kuro was living peaceful in his house, but he hears a big stomp coming towards his house. As he get out of his house and took a look at what was the reason of this big stomp, he gets astonished, because it was an monster, probably 40 times bigger than him!! Lol
Within a few seconds, he and his house gets eaten. Inside the monster's stomach, Kuro was relaxing in his house. After a few minutes, he was launched outside. Kuro thought that he got his peace back, and he went outside to get fresh air, but what he saw outside was an probably an infinite number of monsters marching in line toward his house. He got depressed by this situation and that's where the story ends.
I think the creator of this movie was trying to tell us that there is always an difficulties in our life, and if we don' t take effort to solve it, we can't get out of it.
So,,,,,let's work hard?? Lol