Fixed encounter

A fixed encounter, also known as spiked tiles when referring to games comprised of sprites, refers to a method of entering a battle. Fixed encounters differ from the basic random encounters due to their fixed nature. A fixed encounter is started when a player steps on a certain tile or over a certain area. There are two common uses for fixed encounters, the first being to enter a surprise battle against bosses or stronger enemies. The second use is to impede the player, or to protect an area such as a Treasure Chest. While fixed encounters are a more common feature in the earlier games, they still have appeared in later games in the series.

Final Fantasy
Fixed encounters are mainly used to protect chests. In the Chaos Shrine, two to three Gargoyle enemies can be fought as a fixed encounter. Two to four Piscodemon enemies are fought on floor B3 of the Marsh Cave protecting a Crown. Two to six Anaconda enemies are also fought on the same floor. In the Western Keep, two formations of two to six Mummy enemies can be fought, as well as a formation of two to six Wraith enemies. On floor B1 of the Cavern of Earth, there is a fixed encounter against the Earth Elemental enemy. There is also a fixed encounter against one or two Hill Gigas enemies, and another fixed encounter with the addition of zero to three Lizard enemies. On B3 there is another fixed-tile against the Earth Elemental. On B4 of the Cavern of Earth a single or pair of Sphinx enemies exist in a fixed encounter, as does an Ogre Mage, alongside an Ogre Chief, with the possibility of one or two Hyenadon enemies.

B1 of the Cavern of Earth is notable for having the entire left side of the room covered in spiked tiles against either the Hill Gigas or Lizard encounter.

In Mount Gulg, one or two Fire Elemental enemies can be fought in a fixed encounter. A single Lava Worm is found on the same floor. On B4, an encounter with a single Lava Worm exists, and another encounter with a Fire Lizard. On B5 there is a fixed encounter with a single Fire Lizard, and another with a single Red Dragon.

On B2 of the Ice Cave, one to four Dark Wizard enemies are fought, and a single Evil Eye enemy. On B3, there is an encounter with one to five Specter enemies, with the potential additions of one to three Wraith, one to three Wight, and one to three Ghast enemies. Another fixed encounter on the same floor is against three to seven Winter Wolf, and another with one to two White Dragon enemies.

In the Citadel of Trials, 2F holds a fixed encounter against one to three Clay Golem enemies. The third floor has one against one to two Nightmare enemies, and another against one to two Dragon Zombie enemies. In the Sunken Shrine, on 2F, there are four fixed encounters. The first has one to six Sea Scorpion, two to five Sea Snake, and two Sea Troll enemies. The second one has one or two White Shark enemies and the possiblity of a Sahagin Prince. One to three Water Elemental enemies is the third one. The fourth one is one to five King Mummy, and the chance of one to eight Mummy, one to eight Cockatrice, and one to eight Pyrolisk enemies.

In the Waterfall Cavern, the fixed encounter includes one to five King Mummy enemy, and the chance of one to eight Mummy, one to eight Cockatrice, and one to eight Pyrolisk enemies. In the Mirage Tower, on 3F, a single Blue Dragon can be fought. In the Chaos Shrine of the past, there are four semi-boss battle fixed encounters, complete with the Boss Theme. On B1, surrounding the stairs to B2, the tiles are all fixed to engage in a battle against Lich. On B2, protecting the stairs to B3, a single Marilith is fought. On B3, protecting the stairs to B4, a single Kraken is fought. On B4, protecting the descent to the final floor, a fixed encounter against Tiamat blocks the path.

Final Fantasy II
Fixed encounters are heavily used in Final Fantasy II, often in the form of numerous trap rooms found in many of the games Dungeons. Trap rooms are rooms comprised of many spiked tiles that the user cannot avoid. Since the player starts in the center of the room, a minimum of two encounters have to be fought before the player can leave the room.

Final Fantasy IV
In the Lair of the Father, on the path leading to Bahamut, three single Behemoth enemies are fought when the player travels over the single-tile thick bridges, and therefore cannot be avoided.

Final Fantasy V
Many boss fights are fought using fixed encounters. When escaping Karnak Castle, a seemingly normal encounter against a Sergeant and two Cur Nakk enemies ensue, which later reveals itself to be a boss fight against the Iron Claw. In Drakenvale, a special boss fight involving a Zombie Dragon and a Bone Dragon which attack the Golem in a battle where the object is to save the Golem.

Final Fantasy VII
When on the train that takes the player to North Corel from Mt. Corel during the Huge Materia mission on Disk 2, the player faces an encounter on every carriage they jump on.

Crisis Core -Final Fantasy VII-
Since encounters can only happen in certain areas, there are no random encounters in Crisis Core -Final Fantasy VII-, instead the game is mainly comprised of fixed encounters. Many battles can be avoided by running around the perimeter of the area, however in other areas it is difficult to do this.

Final Fantasy IX
Fixed encounters are used in Memoria. When traveling through the linear dungeon, the player will enter in four different fights in fixed positions against each of the Four Fiends. This is reminiscent of how the Four Fiends of the original Final Fantasy are fought as fixed encounters at the end of the four final floors.