Admin account was hacked. They appear to be working on it:
EDIT: Looks like things are starting to resolve.
EDIT 2: MichelleG account admin was restored and she posted and update but shortly after the changes happened again. Her account is likely still compromised with someone else accessing things via it.
EDIT 3: lemmy.world back online. MichelleG has again been removed as admin. Most things appear to have been cleaned up. Blocked instances still need to be fixed however.