Its high horsepower lets it survive a crap ton of attacks, but it is still vulnerable to attacks that are mainly weakened by high stench levels.
It has a low clasp, and has no special moves other than various enemy moves, which are weaker when used by Pelb. Pelb doesn't use Sploogus. Though, it's high gluttony somewhat counteracts that, but Pelb is still extremely weak.
And Pelb changes the endings.
Completing the game with Pelb as the first Brongus results in an ending where Scrimmy is killed.
However, completing the game with Pelb as an additional Brongus results in a fight against Pelb, with your first Brongus (and any other Brongi) permanently dead.