You can only have one megathread megathread
Says who?
Logic. Use your head. How can there be a mega thread for a thread supposed to contain all other megathreads? There can't be several threads that are supposed to contain all threads. It's not a paradox, because it can't go that far. One thread is supposed to contain all other threads, so there can't be two, because the one thread already did its job. If it didn't do its job it isn't what it claims to be.
Megathread Megathread Megathread