Vicious Bomb, sometimes called Hard Candy Bomb is a blocker in some fanons.
In CC811 it is first featured in level 1061, in the 68th episode.
It is going to appear in T9CCS, but likely in the far future (after level 1000).
In C437CCS, it will first be featured in Level 1271, in the 85th episode.
Candy Crush Special Saga
A variant of this blocker appears in CCSS, called Unstable Candy Bomb. Like vicious candy bombs, it can only be affected by special candies. The difference is that hitting an unstable candy bomb with special candies reduces the timer instead of getting rid of it. Also, the timer only ticks down when it is hit, rather than once every move.
In ECCCS, a similar blocker appears, called the Pancake Bomb. They can only be destroyed by exploding, but a candy bomb exploding usually ends the level. As a result, they need to explode on a safety tile to keep the level going.
Vicious bombs look like normal candy bombs and have the same characteristics, but they will always be black and can only be removed by special candy effects.