New Game Design/Gameplay needed for dealing with Enemies in future games

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I'd like an enemy that you can't HEAR. The hammerhead shark would have been a great chance to make such an enemy, or any kind of marine life. You have to spot it to be able to avoid it. Sure: The angler fish is such an enemy, but you can spot it a mile away. The reason why people feared the creeper in Minecraft, was because you could barely hear it.

That's why I would like to see an enemy that also uses the sneak mechanic not just the player, I see great potential in that idea but it would a hard task to program.

How would it be difficult to program? You could just remove or lesser the sound, and let it loose inside a maze. Also give it fairly good sight so that if you can spot it, it will come for you.
How to beat it? Simple.
There are small items scattered about the level. Scatter more on the floor at strategic locations to improve your chances. The monster will sneak into them and make noise. ...and maybe there's broken glass on the floor at some places too. If you know which way the monster is taking, you can sneak the other way.

I was more talking about a more advance sneaking technique for the enemy, one that would use shadows to hide itself,hiding every nook it can find and attack the player when it's less expected or wait in said nook and wait for the player to come by and ambush them, an enemy that is more cunning than dangerous and plans their attack.