Damage floor

Damage Floors are a recurring feature in the series, most prominent in early installments. They are often traps in nature, damaging the party's HP either by a minute amount, or by reducing them to critical HP. In most installments that they appear in, the player is forced to walk through damage floors in order to progress in dungeons, though in some games, the player may press switches or use certain abilities to bypass damage floors.

Final Fantasy III
In the DS version, the only instance of damage floors appear in the Molten Cave, where standing in the lava will constantly damage the party. In the NES version, this does not happen as the lava is just water colored red.

Final Fantasy IV
In the Sylph Cave and the Passage of the Eidolons, the player may be damaged if they step on green tiles (for the Sylph Cave) or red tiles (for the Passage of the Eidolons). These tiles also appear in the Advance remake in the Lunar Ruins. However, if the player casts Float on the party in the menu before walking across these tiles, they can avoid taking damage.

Final Fantasy VII
Only a couple areas in the game have floors or specific areas that damage the player. In the Cave of the Gi, if the player runs across an area covered in brown liquid in the third screen instead of walking, the player will be thrown into a wall of spikes. In the Ancient Forest, if the player steps on a flytrap, the party's HP will be reduced to 1. Ironically enough, if a party member is at 0 HP, they will be revived with 1 HP when this happens.