Besides collecting a string of boy Robins, along the way Batman has kept souvenirs/trophies from his battles and adventures in the Batcave.
Over the years, he has gone against Superman, Green Lantern, a Tyrannosaurus Rex and many enemies, collecting a series of artifacts and weapons along the way. Among them are costumes of old friends and foes, oversized props, and even mechanical dinosaurs. But what other cool stuff does Batman have hidden in the Batcave?
A Kryptonite Ring
After discovering that the villain Metallo was powered by a heart made of Kryptonite, Lex Luthor used a sample to fashion a Kryptonite ring for himself. He wore the ring at all times in an effort to keep Superman away from him. The ring eventually came into the possession of the Batman. Although Batman is Superman’s closest ally, he keeps the ring secured in the Batcave in case Superman ever loses control of his powers or if he falls under the control of an evil influence (such as Eclipso). On several occasions, Batman has been required to use the ring to keep Superman at bay. (Action Comics #654)
Batman has fought Deathstroke on a number of occasions and has since acquired his sword which now rests in the Batcave.
A Giant Penny
Joe Coyne earned pennies peddling newspapers, lost a job for pitching pennies in the office, and began a career in crime by robbing a cash register stuffed with pennies. Coyne learned to embrace the symbol of his failure, however, and he carved out a corner of the underworld by specializing in penny-themed crimes. He was eventually defeated by Batman, but to this day Batman keeps a gigantic penny in the Batcave as a souvenir of their battle. The coin is not associated with Two-Face, as most people think. (World’s Finest Comics #30, 1947)
Two Face’s Original Coin
As Two-Face, Harvey Dent is rarely seen without his coin, although whether the coin he uses at any given time is the same one his father used, the new one he took, or another coin altogether is never explained. Batman has also been known to keep one of the scarred coins in his trophy room, one of which was nearly stolen by thieves who broke into the Batcave (Batman #577).
A Letter From Thomas Wayne
When the Reverse Flash disrupts the natural flow of the New Earth timeline (The DCU’s main continuity) and the initiates the events of Flashpoint, the past is radically changed. Rather than Thomas and Martha Wayne being gunned down by Joe Chill, it was Bruce that died in crime alley that fateful night, leaving Thomas Wayne alive and broken. Dr. Wayne ages into a very bitter, argumentative, and lonely man, who owns a chain of hotels and Wayne Casino. He has taken on the Batman mantle himself, but unlike Bruce has no qualms about killing. Before he must sacrifice himself to save both his son and his son’s world, he pens an emotional letter to his son in the hopes that the Flash can deliver it. When the timeline is restored, the letter still exists. The Flash gives the letter to Bruce Wayne and now has a place in the Batcave.
While not exactly a trophy, The Batcomputer is too cool not to mention. It can literally do anything (including analyzing DNA and find anyone anywhere). The Bat-Computer is one of the most highly advanced computer hardware systems in the entire world. The first Batcomputer was nicknamed “Dupin” after fictional French detective C. Auguste Dupin. The Batcomputer has a direct link to the Brother Eye satellite, and was once co-opted in order to take remote command of the various OMAC agents. In the continuity of the 2004 animated series The Batman, Bruce Wayne’s batcomputer is known as the Bat-Wave.
A Robot Superman
A Superman Robot was created by a supervillain with alien technology after analyzing Superman’s cellular structure. Similar robots were created of the other members of the Justice League. This occurred in the animated series The Batman’s final episode.
The Oversized Joker Playing Card
A giant replica of the Joker’s playing card appears in the Batcave. The card was obtained during “Topsy Turvy”, the tenth episode of the first season of The Batman. The Batman investigates a crime bearing the stamp of his arch-enemy The Joker, despite the fact that Joker is currently and has in fact remained locked up in Arkham since Batman first put him there. A trail of victims encased in larger than life playing cards leads The Batman to the bizarre truth: Joker’s plan is to turn those who were responsible for putting him away in jail, all fifty-two of them, into giant playing cards, in which the only thing they can move is their eyes. Joker’s ultimate plot is to turn his enemies into a full deck of cards and then toss them into the Gotham River!
Giant Scarface’s Head
Obtainted during “The Big Dummy”, the ninth episode of the first season of The Batman, the Giant Scarface’s Head hangs against the wall in the Batcave. It belonged to Arnold Wesker, a ventriloquist who controls Scarface, a living puppet.
The Mechanical Tyrannosaurus Rex
Arguably the most famous trophy Batman has is the Mechanical T-Rex. The T. Rex comes from an adventure on “Dinosaur Island” (Batman #35, 1946). After battling this mechanical beast in the Gotham amusement park called “Dinosaur Island” (II), he brought it back as a trophy, putting it on display in the Batcave for years. It was eventually lost when Gotham was struck by the earthquake called “the Cataclysm”. Although Batman and Robin fought the Tyrannosaurus Rex in “The Isle That Time Forgot” (Batman #11), it was an Apatosaurus (a.k.a. Brontosaurus) that first showed up in the Batcave. Not until the 1950s, it was retconned into a T-Rex. In 1997, the island from which it originated was retconned from a movie set into an amusement park.
The most obvious thing Batman keeps in the Batcave is bats. Alfred Pennyworth feeds the bats. According to Alfred, they prefer free-range corn-fed chicken goujons, gently fried in extra virgin olive oil.
Probably in the cave too:
A Green Lantern Ring
A Room full of Magic items
Thomas Wayne’s Batman Costume
Mr. Freeze’s First Freeze Gun
The Penguin’s Artifacts
The Mummy’s Case
A Phantom Zone Projector
The Big Dice
Riddler’s Giant Hourglasses
The Penguin’s Umbrella
Killer Croc’s Tooth
Kabuki Twins Masks
Giant Bowling Pins
The Monk’s Hood
Gavel of Judge Clay
The Diary of Dana Drye
A Riddler Question Mark
Mask and Cloak of Clayface I
40’s and 50’s Batmobiles
A Joker Mask
A Bulletproof Vest