While an elephant is minding their own business, eating leaves and grass, a plane carrying large sacks of Chloroplast flies by and one of those sacks falls out
I just realized I haven't eaten
The elephant finds the sack and eats it all in one gulp
chlorophyll is a molecule inside chloroplasts and it is what makes plants look green, so when the elephant eats the sack of chloroplasts, it turns green
THE END
The elephant waits a few days to see if it can go back to its original coloring. After a few days of not going away, he also realizes he hasn't has an appetite.
The elephant now realizes that he has not eaten in a very long time. He remembers that chloroplasts get energy from the sun and realizes he can photosynthesize!
After a while, the elephant becomes grey again and goes back to eating leaves. He lives a very happy life.