Sources
CR
Type
Size
Alignment
Movement

Infant Hook Horror

Tiny Monstrosity, Neutral

Armor Class 10 (natural armor)
Hit Points 4 (1d4 + 2)
Speed 10 ft., climb 10 ft.
STR
9
-1
DEX
10
+0
CON
15
+2
INT
6
-2
WIS
12
+1
CHA
7
-2
Skills Perception +3
Senses blindsight 60 ft., darkvision 120 ft., passive Perception 13
Languages Hook Horror
Challenge 0 (10 XP)

Traits

Echolocation. The hook horror can't use its blindsight while deafened.

Keen Hearing. The hook horror has advantage on Wisdom (Perception) checks that rely on hearing.