Giant Rat (Diseased)

Source: Monster Manual p. 327. Available in the SRD and the Basic Rules (2014)

"name": "Giant Rat (Diseased)"
"size": "Small"
"type": "beast"
"alignment": "Unaligned"
"ac": !!int "12"
"hp": !!int "7"
"hit_dice": "2d6"
"modifier": !!int "2"
"stats":
  - !!int "7"
  - !!int "15"
  - !!int "11"
  - !!int "2"
  - !!int "10"
  - !!int "4"
"speed": "30 ft."
"senses": "darkvision 60 ft., passive Perception 10"
"languages": ""
"cr": "1/8"
"traits":
  - "desc": "The rat has advantage on Wisdom (Perception) checks that rely on smell."
    "name": "Keen Smell"
  - "desc": "The rat has advantage on an attack roll against a creature if at least\
      \ one of the rat's allies is within 5 feet of the creature and the ally isn't\
      \ incapacitated."
    "name": "Pack Tactics"
"actions":
  - "desc": "*Melee Weapon Attack:* +4 to hit, reach 5 ft., one target. *Hit:* 4 (1d4\
      \ + 2) piercing damage. If the target is a creature, it must succeed on a DC\
      \ 10 Constitution saving throw or contract a disease. Until the disease is cured,\
      \ the target can't regain hit points except by magical means, and the target's\
      \ hit point maximum decreases by 3 (1d6) every 24 hours. If the target's hit\
      \ point maximum drops to 0 as a result of this disease, the target dies."
    "name": "Bite"
"source":
  - "MM"

Environment

underdark, forest, swamp, urban