Her name is well deserved, as she’s the daughter of Insanity and Fear.
Macu spends his time looking for kind and giving people who he rewards in some small way. He does this by disguising himself as a needy person, maybe an injured traveler on the road, or a beggar in a town. The first person that responds kindly to him will receive some assistance in the endeavors, they will find out about the assistance when Macu has finished helping them. If a party member is simply indifferent to Macu then Macu will give the party another chance, in a different situation, if the party is still indifferent then he will leave them alone without interfering with them anymore. If the party is cruel or evil in anyway to Macu then he will punish them is some suitable way that matches their evilness. He will even show himself to them so that they will recognize him and the fact that they were evil/cruel to him.
These little beetles have heads at both ends of their bodies. This allows them to feed on leaves at twice the rate of their normal cousins, causing great damage to crops. They look like ladybugs more than actual beetles, but have no wings. They have a funny way of moving if one stops to watch them, as both heads seem to vie for picking the direction at any given time. Their favorite nourishment is sugar cane. After feasting on these for some time, they develop short bursts of frenetic energy, and can be seen racing back and forth without purpose, which looks quite comical to onlookers. They are otherwise normal bugs. Of course the pc's might not know that.