Mastiff

Medium beast, unaligned
Armor Class 12
Hit Points 5 (1d8 + 1)
Speed 40 ft.
STR
13 (+1)
DEX
14 (+2)
CON
12 (+1)
INT
3 (-4)
WIS
12 (+1)
CHA
7 (-2)
Skills Perception +3
Senses passive Perception 13
Languages -
Challenge 1/8 (25 XP)

Keen Hearing and Smell. The mastiff has advantage on Wisdom (Perception) checks that rely on hearing or smell.

ACTIONS

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) piercing damage. If the target is a creature, it must succeed on a DC 11 Strength saving throw or be knocked prone.

Mastiffs are impressive hounds prized by humanoids for their loyalty and keen senses.
Monster Manual (SRD) D&D 5 › Monsters