Not sure if anyone has ever thought about there being a new kind of Creeper in the game, but it would be an idea that I'm thinking would be good.
I had three different names that came to mind. Either Grand Creeper, Adult Creeper and Ancient Creeper.
This new Creeper (whatever it's name) is much more dangerous. It is has been Creeping around for a very long time and has become stronger and even quieter and can move faster than a regular Creeper.
It is also bigger in size physically, taller than the players character. It's colour is slightly deeper green and with a different pattern on it, indicating evolution into this new older type.
It has much more health than a regular Creeper and is immune to arrows because of it's thicker armour. Hitting it with a close-range weapon will hurt it but hitting it when it tries to explode will hurt the player, but will still prevent it from exploding temporarily.
When this Grand Creeper explodes, it is a much more massive explosion and has more force that can send the player and any mob nearby a great distance, including high into the air. The explosion can be deadly to anything nearby without proper protection from armour or strong walls. The blast can penetrate through 2 layers of stone.
Thanks for reading. Any questions or additions, please post