On the character sheet the spore druid's symbiotic entity doesn't combine with the shillelagh attack when I add it in the custom hotkeys. Symbiotic entity damage is added when selected for other melee attacks. It seems like a bug, but maybe symbiotic entity isn't supposed to interact with shillelagh? 

This system isn't designed for temporary effects like Symbiotic Entity. So it will not have any interaction with any melee attacks on your sheet.

It's up to you to remember if you're using it and make a melee attack, you can roll 1d6 necro damage. 

Quote from Cyb3rM1nd >>

This system isn't designed for temporary effects like Symbiotic Entity. So it will not have any interaction with any melee attacks on your sheet.

It's up to you to remember if you're using it and make a melee attack, you can roll 1d6 necro damage. 

 There actually is a hotkey button with Beyond20 that lets you add the effect, and it does work with regular melee attacks. It doesn't work with shillelagh or the custom attack I tried making.

I guess I didn't mention Beyond20. I've been using it for so long I guess I kind of think of it as a standard part of the character sheet.

I had the feeling it was Beyond20.

I've made homebrew weapons to replicate Shillelagh before, using a d8 melee base weapon that the character has proficiency in, with the modifier Bonus: Magic Item Attack With Wisdom (or whichever spellcasting ability) and adding extra modifiers as needed (e.g. Replace Damage Type: Bludgeoning, Ignore Weapon Property: Two-Handed); if you only have Druid weapon proficiencies, you could use greatclub as the base weapon and add the modifier Proficiency: Greatclub so that your attacks will be proficient.

Note that it will make all your magic weapon attacks use Wisdom, so if you have other magic weapons, only equip it when you need to. If you're up for homebrewing a bit, this should work for you.

Quote from naruhoodie >>

I had the feeling it was Beyond20.

I've made homebrew weapons to replicate Shillelagh before, using a d8 melee base weapon that the character has proficiency in, with the modifier Bonus: Magic Item Attack With Wisdom (or whichever spellcasting ability) and adding extra modifiers as needed (e.g. Replace Damage Type: Bludgeoning, Ignore Weapon Property: Two-Handed); if you only have Druid weapon proficiencies, you could use greatclub as the base weapon and add the modifier Proficiency: Greatclub so that your attacks will be proficient.

Note that it will make all your magic weapon attacks use Wisdom, so if you have other magic weapons, only equip it when you need to. If you're up for homebrewing a bit, this should work for you.

 That worked well, thanks! Using the magic item attack: wisdom and ignore versatile property with warhammer:proficiency base. And then I'm not sure why but when I added the necrotic damage it automatically includes it and labels it Symbiotic Entity damage, but if I add a 1d6 for the necrotic damage it added an extra d6 of damage.

So this is weird, adding symbiotic entity as a hotkey for Beyond 20 actually does the reverse of what you think it should do. The custom magic item and rolling the reaction damage for halo of spores (but not shillelagh or normal attacks) is automatically adding the extra 1d6 for symbiotic entity. But when I actually check the Beyond 20 hotkey for symbiotic entity that causes those rolls to act like normal rolls, without SE active.

It's pretty easy to manage, just do the opposite. I'm just putting it out here for anyone else, or developers, having this issue.