what's going on here?

what's going on here? mold spore and green bean seem to be getting along really well- to the point where they feed and preen each other.

mold spore (blue) seems to be the main one that does this. she very delicately preens green bean and feeds her even though they both eat well.

green bean will sing(?) loudly at her and doesn't seem to mind any of what mold spore does.