"Stop right there" entities.

The most popular of them is A-90. It just requires you to stop for a second when you see it's face on the screen. Not so hard, but can be annoying sometimes. The second one I know is... Doser from Grace. He requires you to stop and crouch, or it will instantly kill you. A-90 was just dealing a huge damage, but Doser just kills the player. At least Doser slows the Carnation or Slugfish to the 10% of their original speed.

No lights entities.

You may think that I'd say about Screech, but no. Those are Gloombats. If you use any light source near them, they'll damage you until you don't put it away (glowsticks and laser pointer don't count). Same with Squiddles from Pressure, but they require some time to shine at them before they attack. Also they can be forced to attack player if the player is touching them.

Timer entities.

Do I need to explain how they work? Haste can be stopped by a crucifix (only in the Hotel), and Goatman (Grace) can be flashed by a flashlight (just like the shork girl or Sebby :D ). SUDDENLY, a wild Pizzaface appears. Yeah, the one from the Pizza Tower. He is just overall invincible during the Lap 1, Lap 2, and the escape from the tower itself.

I'm not even tired to write these