Brongi are selectable characters in Scrimmy Bingus And The Crungy Spingus.
They are first picked at the start of the game, but there are various points in the game where you can add an extra Brongus to your travel group, going from having just 1, to having up to 7 in the current travel group(CTG) and an infinite amount in the passive-follow.
There are places in which you can change who's in the passive-follow or CTG, indicated by Nate-Dogg Statues.
(Warning: Do not choose Pelb at the start of the game. There are seperate endings for both having Pelb in your party at all or having it at the start of the game. The worse of the 2 endings is having Pelb at the start, which cuts the game off before the point of ever getting into battle-mode other than the Spingus, which no longer has any action other than tapping green sock creatures.)