rabbit's name is derived from the word marshmellow, because it resembles
a partially bitten one. Mashimaro feels neglected because it is different
from all other rabbits. Due to this, Mashimaro has become a bit twisted
from the rest of society and chooses to act in very strange ways.
This is a way for him to discover and find his own identity, since he is not yet comfortable in his own skin.
Maro Episode 1 (Fishing)