What is the difficulty bomb in Ethereum?

The Ethereum difficulty bomb is an increasing level of computational difficulty in mining algorithms that allows developers to adjust how difficult it is for a miner to receive a reward for the mined block. The difficulty bomb is needed to get all miners to start using the Proof-of-Stake algorithm instead of the Proof-of-Work. The level of difficulty in Ethereum began to rise in 2016 from the 200,000th block.