One porcupine has a black nose and brown eyes and the other porcupine has a red nose and black eyes. They both have light brown fur with cream fur around their mouths and on their chests. Their quills are banded white and brown. They both have clusters of longer fur standing up atop their heads.
The Porcupine Brothers are stubborn and appreciative of assistance.
When floodwaters hit the Pride Lands, they find their home in a log rolled over by the waters. The Lion Guard flip the log back to where it was supposed to be. As the Lion Guard walk away, they argue over the cramped space of the log.
The Porcupine Brothers, along with Mtoto, Young Rhino, Young Hare and most of the Lion Guard, listen to a spooky story told by Rafiki, about a creature known as the Zimwi. He assures them that they don't have to worry, since they only come out on a full moon. Bunga points out that that very night has a full moon, which worries the brothers. They are startled when some bellowing sounds emerge nearby, but discover that it just Beshte practising for an audition with The Bellow Fellows. Rafiki soon continues his story before ushering them all to bed, remaining ambiguous on the authenticity of the Zimwi. As they walk back the wind spooks them, and Kion suggests that they all sleep together that night. The Lion Guard decide to do the same thing, and head back to Hakuna Matata Falls (though not before Beshte's bellowing spooks the youngsters again).
However, the Porcupine Brothers decide to snuggle up with each other nearby, which startles the other animals they were with as well as some nearby gazelles. The Lion Guard encounter the Porcupine Brothers huddled together atop a termite mound and are initially frightened away. When they return with newfound confidence, the Brothers roll off the mound and onto the floor before separating. The Lion Guard are amused, realising that the two Porcupines were in fact the 'Zimwi' that they had been chasing. The Porcupines explain that they were frightened so they snuggled together, and the termite mound had made them appear much taller than they usually were. Relieved, the Lion Guard close the case.
The Porcupine Brothers have a different voice actor in Beware the Zimwi, making them sound much younger.