Some monster abilities will hit multiple characters, so long as they are in front of the mob.
"In front" generally means the 45° arc in the direction the mob is facing.
The cone has a variable lentgth, depending on the monster and ability being used.
These are frequently called "Breath" or "Gaze" attacks by NA players. Gaze attacks are denoted below with a *, and can be avoided by turning one's back on the monster before it uses the ability.
Monster Abilities that are Cone Attacks
Species Ability Effect Antica Magnetite Cloud Weight and Earth damage Bugard Awful Eye Strength Down Bugard Heavy Bellow Stun Crawler Poison Breath Poison Crawler Sticky Thread Slow Taurus Mortal Ray * Doom Eruca Incinerate Fire damage Hound Poison Breath Poison Scorpion Cold Breath Ice damage and Bind Scorpion Numbing Breath Damage and Paralyze Sea Monk Ink Jet Blind
Note that this list is by no means exhaustive.