
Instead, how about we let him evolve into other Plant monsters, which all should have relatively simple and streamlined monster stat blocks? but that would probably get overpowered quickly, and give the shrub too many abilities that would slow play in combat. You could just let them use their monster stats as their racial features and starting ability scores, and staple class levels on top at some throttled rate (figuring out what it takes to earn Level 1 is weird, but maybe hold them back a grade and grant level 1 at 300 XP, level 2 at 900, etc). But, they have no way to use/benefit from that XP, as written. NPCs that aren’t subclass pets are supposed to steal a share of XP when they’re in fights. Oh, and our Druid often Druidcrafts berries out of it if we run out of Goodberries materiel in a dungeon. You can train it, as it's intelligent and can speak, and it's absolutely loyal to you, doing everything you command it to do without eating your bonus actions for commands.

It can even live in your bag of holding only extending branches out to do what you asked it to do, which eliminates slow speed and low HP drawbacks (but it would likely stop it from doing Help action unless your DM is super generous).

As we play with Exploring Eberron I have a bunch of Blast Disks loaded with buffs and the shrub acts as delivery system for those. It can pour potions into your mouth, picks up the longbow you drop when you switch to melee weapon and attack in the same action, searches for items in your bag of holding in battle etc. Some may say that slow 10hp minion with pathetic attack is useless but it gives you extra set of hands (or branches in this case) to do things other than attacking. So I got one in between two campaigns and made my own awakened billbery shrub slave.

Phandelver and Below: The Shattered Obelisk Mordenkainen Presents: Monsters of the Multiverse
