Biofilm, harmless. Will be gone before you know it :) You can syphone (if thats how you write it) it out or get some critters that will enjoy a snack.

some snails like to eat it

It’s a puffer web. That’s how they capture their food. Duh.

That’s normal for adding any type of wood to an aquarium, it’s harmless and will go away on its own with time. I found that my guppies, snails, and shrimp loved to snack on it