SRD
Keen Hearing and Smell The mastiff has Advantage on Wisdom (Perception) checks that rely on hearing or smell.
Bite. Melee Weapon Attack: +3 to hit, reach 5 ft, one target. Hit: 2-4-7 1d6+1 Piercing damage. If the target is a creature, it must succeed on a DC 11 Strength Save or be knocked Prone.