The Regenerating Block is a rather annoying block found inside The Worm.
They can be destroyed with most attacks, but after a few seconds will reappear at the same spot, killing everything inside it, similar to the teleporter. Broken regenerating blocks will be distinguished by a backdrop version in it's place.
They can be one of the most frustrating and annoying block inside The Worm in dire situations, as you will get trapped by them and will most probably die.
Tips for getting past them. Edit
To get past them, try placing bombs down, getting out the blast radius and running through as quickly as possible. (A Mattock is also very useful.)You can also use your whip to break them. Sometimes they will also spawn in big chunks with some gaps in between, and you need to be careful with these structures.