The attacker did a 51% attack on the Goldcoin blockchain. It is supposed to be resistant to that according to this article: https://goldcoinweb.com/press-release/goldcoin-dodges-a-51-attack-that-takes-down-verge-bitcoin-gold-and-monacoin/ It appears that an attacker using wallet E2QkoAZzVJuGt4xNSyLZp8VkeknNAdBfHS and mined the Goldcoin blockchain privately and then modified the Goldcoin blockchain after up to 64 blocks. It is likely that multiple nodes were used in the attack. No public transactions appear on the chain in blocks 884928–884992 . https://i.imgur.com/4btsRpd.png The attack resulted in the discarding of the publicly mined chain in favor of the privately mined chain by the attacker. The attacker send funds at the start of each attack block sequence visible on the block explorer and a double spend on the publicly mined chain targeting exchanges. It does not appear that Goldcoin has enough hashpower to withstand such an attack resulting in hundreds of orphaned blocks mined by the honest miners. https://chainz.cryptoid.info/gld/orphans.dws