Dangerous Terrain is a phenomenon in which some portion of the battlefield between or below the hero and villain is dangerous to both parties. If Dangerous Terrain is present, be assured that at some point during the battle, the hero and villain will wind up in a shoving or wrestling match very nearby, trying to push each other into it. (In videogames, this is a Ring-Out Boss.)
This is a subtrope of Interesting Situation Duel.
- Ranma ½:
- In a sense, the Jusenkyō springs are dangerous, which is possibly why they're advertised as "a legendary training ground."
- Jusendo, the source of Jusenkyō, is explicitly dangerous. Its creators built the place as a huge maze of exploding hatches, trapdoors, dropaway floors, and hidden passages.
- The Water Citadel in the Pantyhose Tarō story arc is a hollowed-out mountain, filled with water at very high pressure. Pantyhose Taro jammed logs into it and loosened enough rocks to make it into a trap for his Jusenkyo-cursed enemies, so that the slightest misstep would turn a rampaging foe into a helpless black pig, a weapons master into a duck, and an Amazon into a cat — and his nemesis into a woman. Worse, Pantyhose Taro himself turns into a gigantic winged minotaur, so splashing him would make him nigh-unbeatable. "Team Ranma" learned to mind their step across the Water Citadel in a hurry.
- The Princess Bride. Westley is wrestling with a Rodent of Unusual Size in the Fire Swamp. He cleverly uses one of the fire spurts to set the ROUS ablaze and distract it, allowing him to finish it off with his sword.
- Pirates of the Caribbean: At World's End climaxes with a ship to ship battle in the middle of a maelstrom. Instead of trying to avoid it, both ships dive in head on, trying to stay out of the worst of it while also taking down their opponent.
- Tarzan's Three Challenges. In the fourth (?) challenge, Tarzan and the villain face each other armed with sabers on a net suspended above vats of boiling oil.
- Star Wars Episode III: Revenge of the Sith: the lava rivers where Anakin loses his limbs.
- Flash Gordon has a pitched duel taking place on a constantly-tilting spike-covered platform above a Bottomless Pit.
- When spoofed in Robin Hood: Men in Tights the fight between Robin and Little John takes place over a creek just a few inches deep. When Little John is knocked off the bridge, he flops around and screams that he's drowning, and after a bewildered Robin pulls him up Little John joins him as per I Owe You My Life.
- The heroes of The Belgariad make their way through an unmarked quicksand maze and then get ambushed by mooks. One mook gets chased into the bog, rides straight off the safe path, and sinks to his doom. Durnik regrets only that he couldn't save the horse.
- Not nearly as dangerous as those already mentioned: in Robin Hood stories he first meets Little John (or sometimes Friar Tuck) when they both want to cross a river on a Lumberjack Bridge; neither will back up so the other can cross first, instead they decide to have a quarterstaff battle in the middle and whoever gets knocked into the water loses.
- Warhammer and Warhammer 40,000 may very well be the Trope Namer. Difficult Terrain is the specific rules term for rubble, undergrowth, and other areas that slow the movement of troops and vehicles. Minefields and such are called Dangerous Terrain, which is Exactly What It Says on the Tin. One edition took it one level higher with Lethal Terrain, which is normally impassable, but if a unit somehow manages to end its move there, it is imidiately removed as a casualty.
- BattleTech features a wide variety of dangerous terrain that require piloting checks to pass safely. Ice on bodies of water can break, dumping the unit into the water; a nuisance to mechs, deadly to tanks. Swamps can cause units to become bogged down. Minefields are hidden, and either explode on contact, by vibration or by player-command. Amusingly, city roads are considered dangerous terrain to the signature Humongous Mecha, as their feet can slip out underneath them if they start turning while running.
- Some of the stages in Soul Calibur II's story mode are like this.
- The original premise of the Dead or Alive games was that it was Virtua Fighter with
titsdanger zones that send you or your opponent flying if they step into them. The developers eventually refined this into having stages that take place on uneven ground, pop-up traps, natural arenas with multiple heights that do tick damage if you fall off or get thrown off them, etc.
- There is the constant threat of the ocean to worry about in Worms. Being worms, they don't swim very well and one default setting for Sudden Death is to slowly rise this water level until the entire map is submerged.
- In the Shin Megami Tensei franchise, some areas have floors that can hurt you. Some take it a step further and have floors that can inflict Status Effects like poison and sleep. A possible strategy with status effect floors is to equip accessories that negate the offending status effect, then put away any demons that don't have the same immunity, but depending on the game this will leave you at the mercy of enemy encounters.
- By definition, any naval or aerial battle, where the combatants on both sides will share two enemies in common: Water and Fire (aviators like to wryly include the ground in this category). Back when battles between ships could be settled at very close range to the point of sword fights between the crews, it was not uncommon for a ship's surrender to be followed immediately by the crews of both ships working together to fight fires and prevent either ship from sinking. Similarly, there are stories of naval battles that were narrowly avoided because one or both fleets was driven off or scattered by a hurricane.