Found it
There was a client i thought that took an approach to generate a new keypair and burn after each event. So like an anon client kinda you didnt login cause it was pointless.
Not exactly what you are talking about and have no idea what the client capability was.
cant remember name nostr:nprofile1qqsr7acdvhf6we9fch94qwhpy0nza36e3tgrtkpku25ppuu80f69kfqpz9mhxue69uhkummnw3ezuamfdejj7qghwaehxw309aex2mrp0yhxummnw3ezucnpdejz7qg4waehxw309aex2mrp0yhxgctdw4eju6t09ug4n6q3 by chance do you remmeber this?
Discussion
Yeah, I've used that before. I think they use PoW to keep spammers from using it. I was thinking of something like that for anon emojis.