Door Imitator

Door Imitator (扉擬態魔) is a type of monster that disguises itself as a door.

Appearance
It relatively appears as a door, though it hides tentacles behind its frame.

Abilities
This monster takes the appearance of an exit waiting for unsuspecting travelers to touch it thinking it's a way out. Once its prey is close, it unravels itself, restraining the opponent with sticky tentacles while attacking.

Trivia

 * This monster is found in YGGDRASIL, but also in the New World as one of the members of Heavy Masher had encountered one before this.
 * An undead version appeared in Nazarick, a seasoned worker could tell by the color of the tentacle.
 * In Isekai Quartet, a Door Imitator was used by Rudersdorf as part of his security system to protect his wine.