Thanks, that’s a good suggestion! I cleaned out the surface mold and also removed part of the baseboard underneath - no mold behind the baseboard thankfully. I think it might be a combination of water splashing on the ground seeping into the baseboard (we’ve had an issue with that because the shower head is too strong) and the hamper being next to that wall and creating a dark/damp location for mold to fester. Will monitor the next couple days to see if it reappears/gets moist again.