Keen Smell. The rat has advantage on Wisdom (Perception) checks that rely on smell.
Actions
Bite. Melee Weapon Attack: +0 to hit, reach 5 ft., one target. Hit: 1 piercing damage.
How the rat compares at CR 0
Against the 28 other challenge 0 monsters in the SRD 5.1, the rat has more hit points than 0 of them, which makes it one of the frailest at its CR. See every CR 0 monster.
Statistic
Rat
CR 0 average
Armor Class
10
11.1
Hit points
1
4
Best attack bonus
+0
+2
Rat 2024 stat block
The 2024 Monster Manual revised the rat, and the SRD 5.2 carries the new stat block. What changed:
Speed: 20 ft. → 20 ft., climb 20 ft..
New in its stat block: Agile.
Gone from it: Keen Smell.
Armor Class
10
Hit Points
1 (1d4 - 1)
Speed
20 ft., climb 20 ft.
Challenge
0 (10 XP)
STR
DEX
CON
INT
WIS
CHA
2 (-4)
11 (+0)
9 (-1)
2 (-4)
10 (+0)
4 (-3)
Senses
darkvision 30 ft., passive Perception 12
Languages
None
Traits
Agile. The rat doesn’t provoke an Opportunity Attack when it moves out of an enemy’s reach.