You may already have heard about it, and you are freaking out, although you do not really understand what it means: The Bitcoin Death Spiral.
What does it mean?
The Bitcoin Death Spiral is related to Bitcoin Mining and the cost to mine one Bitcoin (BTC):

If the cost to mine BTC increases too much (for instance, due to electricity cost), and Bitcoin Price decreases at the same time (due to bear market), many miners will go offline since it is not profitable for them to run their operations anymore, and then Bitcoin’s hash rate will fall, causing its security to be weakened, and for the system to ultimately collapse...
However, this theory needs to take into account the Bitcoin’s difficulty adjustment, which changes roughly every two weeks, as explained by Cory Swan:
as the hash rate falls as unprofitable miners go offline, the difficulty will adjust downwards, making it relatively more rewarding for the miners that stay online. This assures blocks will continue to be mined every 10 minutes and that Bitcoin will live to see another day.
Therefore, according to David Z. Morris:
Difficulty Adjustment Is Why Bitcoin Will Never Die
Unless the electricity cost evolves faster than difficulty adjusment?...