What Is a “Difficulty Bomb” and Which Cryptocurrency Uses It?
A difficulty bomb is a mechanism intentionally coded into a blockchain's protocol that causes the mining difficulty to increase exponentially over time. This makes mining eventually impossible.
Ethereum (ETH) used a difficulty bomb to force a transition from Proof-of-Work (PoW) to Proof-of-Stake (PoS), ensuring the network upgrade (The Merge) would occur.