Traps are basically tiles in the floor with special effects that are activated whenever Ashley steps on them. Most of the time, these effects are negative, resulting in direct or indirect damage to Ashley, although there are traps with beneficial effects. A trap is completely invisible, indistinguishable from any other space in the room, until one of two things happens: Ashley steps on it or reveals it via the Eureka spell or Eye of Argon item. At that point, the trap will start to glow; however, if you leave the room and come back in, it will be hidden once again. If it is disarmed via a Trap Clear trap, it will rearm when Ashley leaves the room.

Traps cannot kill Ashley directly, and none of the traps that does direct damage will be able to deplete his HP entirely. However, they can easily kill him indirectly, by causing negative, potentially deadly status changes, or by weakening him for the benefit of any enemies in the room. If Ashley is in Battle Mode when he steps on a trap, his armour will protect him against that trap, and he will take less damage than he would have outside of Battle Mode. Similarly, any Gems for defending against negative status changes that might be equipped on Ashley's armour will be in effect if Ashley is in Battle Mode when he trips the trap.

Traps will affect enemies if they trigger them, so you can try to use this to your advantage. It will rarely be a viable scenario, though. Lastly, falling off a cliff or into a hole or waterway will automatically do 20 HP of damage to Ashley, regardless of his armour. Unlike stepping on a trap, falling off cliffs can kill Ashley directly.