System Reference Document 5.2.1
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 CR.  Challenge Rating summarizes the threat a 
monster poses and is detailed in “Monsters.” The 
Experience Points characters receive for defeating 
a monster and its Proficiency Bonus follow. Some 
creatures that are created by magic have no CR. See 
also “Challenge Rating” and “Experience Points.”
 Traits. The monster’s traits, if any, are features 
that are active at all times or in certain situations.
 Actions.  The monster can take these actions in 
addition to those detailed in this glossary. See also  
“Playing the Game” (“Actions”).
 Bonus Actions. If the monster has Bonus Action 
options, they are listed in this section.
 Reactions. If the monster can take special Reac -
tions, those are listed in this section.
 Attack Notation. The entry for a monster’s attack 
starts by identifying whether the attack is a melee 
or a ranged attack and then provides the attack 
roll’s bonus, its reach or range, and what happens 
on a hit. An attack is against one target unless its 
entry says otherwise.
 Saving Throw Effect Notation. If an effect forces 
a saving throw, the effect’s entry starts by identify -
ing the kind of saving throw required and then pro -
vides the save’s DC, a description of which creatures 
must make the save, and what happens on a failed 
or a successful save.
 Damage Notation. A stat block usually provides 
both a static number and a die expression for each 
instance of damage. For example, an attack might 
deal 4 (1d4 + 2) damage on a hit. The GM deter -
mines whether you use the static number or the die 
expression in parentheses; you don’t use both.
Study [Action]
When you take the Study action, you make an Intel -
ligence check to study your memory, a book, a clue, 
or another source of knowledge and call to mind an 
important piece of information about it.
 The Areas of Knowledge table suggests which 
skills are applicable to various areas of knowledge.
Areas of Knowledge
Skill Areas
Arcana Spells, magic items, eldritch symbols, 
magical traditions, planes of existence, 
and certain creatures (Aberrations, 
Constructs, Elementals, Fey, and 
Monstrosities)
History Historic events and people, ancient 
civilizations, wars, and certain creatures 
(Giants and Humanoids)
Investigation Traps, ciphers, riddles, and gadgetry
Nature Terrain, flora, weather, and certain 
creatures (Beasts, Dragons, Oozes, and 
Plants)
Religion Deities, religious hierarchies and rites, 
holy symbols, cults, and certain crea -
tures (Celestials, Fiends, and Undead)
Stunned [Condition]
While you have the Stunned condition, you experi -
ence the following effects.
 Incapacitated.  You have the Incapacitated 
condition.
 Saving Throws Affected. You automatically fail 
Strength and Dexterity saving throws.
 Attacks Affected.  Attack rolls against you have 
Advantage.
Suffocation [Hazard]
A creature can hold its breath for a number of 
minutes equal to 1 plus its Constitution modifier 
(minimum of 30 seconds) before suffocation begins. 
When a creature runs out of breath or is choking, 
it gains 1 Exhaustion level at the end of each of 
its turns. When a creature can breathe again, it 
removes all levels of Exhaustion it gained from 
suffocating.
Surprise
If a creature is caught unawares by the start of 
combat, that creature is surprised, which causes it 
to have Disadvantage on its Initiative roll. See also  
“Playing the Game” (“Combat”).
Swimming
While you’re swimming, each foot of movement 
costs 1 extra foot (2 extra feet in Difficult Terrain). 
You ignore this extra cost if you have a Swim Speed 
and use it to swim. At the GM’s option, moving any 
distance in rough water might require a successful 
DC 15 Strength (Athletics) check.
Swim Speed
A Swim Speed can be used to swim without expend -
ing the extra movement normally associated with 
swimming. See also  “Swimming” and “Speed.”