94. Killer Croc
FIRST APPEARANCE: BATMAN #357 (1983) Killer Croc is one of the more, shall we say...outlandish villains that Bruce Wayne has faced over the years; while The Riddler, The Joker, The Penguin and Bane could be relatively rooted in various degrees, there's absolutely no way to make Croc plausible (sorry, Christopher Nolan). His character has inherited traits from reptiles, while a so-called "metagene" serves to enhance those characteristics, namely his super-human speed and strength. His reptile-like skin is also refined to such an extent that it can withstand heavy gunfire, acting like a strong armour of sorts, and much like actual lizards, he can regenerate lost limbs, as well as heal himself during battle. The key to his defeat? Drawing him out of water, because it slows him down and leaves him more open to attack. Personality-wise, he hates humanity and is resentful of his appearance, using his heightened sense of smell to track people down from miles away and devour them. He enters at a modest #92 because, unlike most of Batman's foes, he's not intellectual in the slightest; he's pure, brute force, meaning he's nowhere near as interesting as foes such as Bane and The Joker (who we'll encounter a little ways later).
93. Zoom
FIRST APPEARANCE: THE FLASH (VOL. 2) #197 (2003) A relatively new addition to The Flash's roster of enemies, but also one of his most potent and well thought-out. Zoom, initially introduced as Hunter Zolomon two years before his transformation. This occurred when he was working as a cop and a prison break began, so he decided to break into the Flash Museum and use the cosmic treadmill to prevent this, but ended up "disconnecting" himself from his present timeline, allowing him the power to move through time as quickly or slowly as he so desired. However, this had a profoundly disturbing effect on Zolomon's mental state, as he came to believe that if he could create a tragedy in (the then Flash) Wally West's life, it would make him a more efficient superhero. Of course, it's easy to see from this how he came to be feared as a foe of The Flash's, though he is distinguished for being among the few able to keep pace with the speedy hero. Though The Flash has foiled him every time, their dichotomy - the yin-yang nature of their relationship - makes for a compelling stand-off every time.
92. Mephisto
FIRST APPEARANCE: SILVER SURFER #3 (1968) Don't be fooled by the name; though Mephisto's moniker might suggest that he is, in fact, Mephistopheles aka The Devil, that is simply something he is counting on; he is an imposter who uses humanity's belief in the Devil to take on that guise unchallenged. With this belief, he has managed to preside over his own dark realm, though does find his powers severely curtailed when he ventures to Earth to cause trouble for Silver Surfer, Fantastic Four, Dr Strange and Ghost-Rider and the rest of Earth. Mephisto enjoys deceiving and causing misery, praying upon even the superheroes themselves in their darkest hours, such as when he offered to revive Aunt May for Spider-Man, but at the cost of his relationship with Mary Jane. One of the most powerful Marvel foes, Mephisto is capable of tremendous manipulation both physical and mental; he can shape-shift, and also project hallucinations to confuse his enemies, as well as alter time on occasion. What's more, if his physical form is destroyed, he simply reforms in his own realm and can go at it again.