Does the Fathomless Warlock's Tentacle of the Deeps occupy space?

Question

Even if the feature itself doesn't describe the tentacle as being a creature, it does describe its size (A 10-foot long tentacle).

So would it occupy its space/a square and impede movement from foes?

Answer 1

The tentacle does not occupy space.

The tentacle is not stated to be a creature or an object and is not stated to have a controlled space or reach. Since the rules don't say it does occupy space and don't specify that it is a thing that occupies space by default, we assume it does not. Furthermore, the tentacle is stated to be "spectral", which means ghostly and insubstantial, which suggests that it is at least somewhat immaterial (apart from when it's doing its thing).

This is very similar to spell effects like a spiritual weapon, which is similarly "spectral" and is not stated to occupy space. As an example of the contrary position, consider guardian of faith, which conjures a "large spectral guardian" that specifically "occupies its space".

Answer 2

Probably not.

As you have observed, the tentacle does not count as a creature, and the description states:

You can magically summon a spectral tentacle that strikes at your foes.

The tentacle is spectral, which means something like "like a ghost or specter". The idea here seems to be that the ghost is incorporeal or intangible, like a ghost. To further support this, we see that the tentacle deals cold damage when it damages a creature, rather than a physical damage type like bludgeoning. Given these observations, I would rule that the tentacle does not "occupy its space" or impede movement through the space it is in.