Wyatt's got a thing where he makes sample companions, which got me for some reason thinking about the baby owlbear from The Whispering Cairn. Companions were "officially" introduced in Dungeon Master's Guide 2, and are mostly used to fill out empty party slots and/or as guest stars for an encounter or two. I think they would also be awesome for players that are dead, or if the party is split up. I know I had fun playing the dog in Dragon Age.
Anywho, if you decide to run Age of Worms (again?), here's a stat block for the lil' guy.
Notes: Removed double attack, though I could see that being added back in at a later level as an encounter attack. Reduced stunning screech so that it only dazes for a turn instead of save ends (though I could see it gradually scaling back up to that point).