Hola, espero que estés teniendo un gran año.
I think it might be called the "tail." I might be getting this mixed up with a comet, but I THINK(emphasis on think ^^') they're similar in that aspect?? Sorry if this didn't help.
Wind erosion is the main cause. And since it is the desert that wind can pick up tiny sand rock particles that slowly grind against the rock. Over time the erosion will give a jagged rock the smooth features as if it had been submerged in a river for the roughly same period of time.
Answer:
The anwser is a shore
Explanation: This is because land meets at shores where the water stops.
