Doppelganger
Medium monstrosity, unaligned
STR
11
DEX
18
CON
14
INT
11
WIS
12
CHA
14
Armor Class: 14
Hit Points: 52 (8d8+16)
Speed: Walk 30 ft., Swim
Challenge Rating: 3 (700 XP)
Saving Throws:
Skills: Deception +6 Insight +3
Senses: darkvision 60 ft. passive perception 11
Languages: Common
Shapechanger
The doppelganger can use its action to polymorph into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
Ambusher
In the first round of combat, the doppelganger has advantage on attack rolls against any creature it has surprised.
Surprise Attack
If the doppelganger surprises a creature and hits it with an attack during the first round of combat, the target takes an extra 10 (3d6) damage from the attack.
Actions
Multiattack
The doppelganger makes two melee attacks.
Slam
Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) bludgeoning damage.
Read Thoughts
The doppelganger magically reads the surface thoughts of one creature within 60 ft. of it. The effect can penetrate barriers, but 3 ft. of wood or dirt, 2 ft. of stone, 2 inches of metal, or a thin sheet of lead blocks it. While the target is in range, the doppelganger can continue reading its thoughts, as long as the doppelganger's concentration isn't broken (as if concentrating on a spell). While reading the target's mind, the doppelganger has advantage on Wisdom (Insight) and Charisma (Deception, Intimidation, and Persuasion) checks against the target.