Cuckoo Cycle is a different flavor of proof-of-work that requires finding cycles in large, memory-intensive graphs. This approach tries to limit ASIC advantage by emphasizing memory bandwidth over pure hash power. Several altcoins have toyed with it in pursuit of ‘ASIC resistance.’

While it’s an interesting concept, it has no place in Bitcoin’s consensus, which remains firmly anchored to SHA-256. The name ‘Cuckoo’ references the cycle-detection puzzle, not an actual nest full of baby birds (though some might wish to see curious feathers in the blockchain world).