Bomb-Fish or The creepers of the sea (hard mode)

Players nowadays like to make underwater homes because creepers can't blow things up in the water.
So, let's make this more intense. This mob will only spawn in hard mode so don't worry. Now, this creature is the size of a stage one pufferfish, when it gets close it will slowly expand showing a type of creeper face on it's belly then exploding. They won't randomly attack players that are swimming by but they cling onto blocks that are in the water. Most likely underwater houses. If they cling on, it will be a pain to remove them. If you punch them while they are sticking on your house, they will immediately explode leaving a large hole in your house.
Players are gonna hate me but this is just for hardmode.