10 Worst Things Batman Did To Villains
2. Torturing Mad Hatter... And Leaving Him To Drown - Batman: The Dark Knight #21
Apparently sometimes torture isn't enough for the Batman.
In a series of the same name as the one from the previous entry yet with a completely different creative team, Batman gets angry after a friend of his is killed by the Mad Hatter.
This anger is to such a degree that when he tracks down the Hatter, the villain is treated to a beating that even forces Alfred to plead with Bruce to stop. Batman throws Tetch through a bunch of his Alice In Wonderland themed scenery, then proceeds to punch him to a near-death state, before finally throwing him in a nearby lake. Ultimately, Alfred convinces Bruce to pull Hatter from the water - but it takes a long time.
The most twisted element of this scene is that Batman seems to enjoy it as he greets Mad Hatter with a wide grin just before carrying out his onslaught.