Aberrant Ground. the ground in a 10-foot radius around the mouther is doughlike difficult terrain. Each creature that starts its turn in this area must succeed on a DC 10 strength saving throw or have its speed reduced to 5 until it's next turn. Gibbering. The mouther babbles incoherently while it can see any creature and isn't incapacitated. Each creature that starts its turn within 20 feet of the mouther and can hear the gibbering must succeed on a DC 10 wisdom saving throw. On a failure, the creature can't take reactions until the start of its next turn.
multiattack the gibbering mouther makes one bite attack and, if it can, one blinding spittle attack bites weapon attack: +2 to hit, reach 5 ft.,one creature. Hit: 9 (3d6) piercing damage. If the target is medium or smaller, it must succeed on a DC 10 strength saving throw or be knocked prone. If the target is killed by the damage, it is absorbed into the mouther. Blinding Spittle (Recharge 5-6). The mouther spits a chemical glob at a point it can see within 15 feet of it. The glob explodes in a blinding flash of light on impact. Each creature within 5 feet of the flash must succeed on a DC 13 dexterity saving throw or be blinded until the mouther's next turn.