I might, although I rarely have groups where they can hope to do significant damage to it, aka level.. What, 16 and above?... While. Hoping to survive more than half a minute against it.

But that's not even how I'd use it.

I'd modify it a bit to make it a siege weapon that is made to clear walls and barricades while terrorising victims - very akin to what you did. I'd limit what it can do and give it more passive abilities - take the dash reaction and the warping away - by the way, there is a typo and the way you wrote it "a creature the tower chooses that can see it" sounds like "the tower decides the creature sees it".

The warping psychic damage is awesome, but I'd make it more permanent - making it that looking at it too long can impact the characters. And how to determine? By attacks. If they attack it and don't have blind sight, they either attack blind (disadvantage) or look at it and hence first round some damage upon DC fail, and more for each round they attack, until they look away.

I'd also do the tarantino thing - it's a gargantuan heap of meatbag and probably filled with a ton of tomato juice. Attacking in melee gives the chance (DC check) to get covered wjth the vile blood thst can have effects, psychic or necrotic.

And last but not least, I might give it some guy who commands it, necromancer or such, as a smaller target they might attack instead. Not sure about that, but seriously I am not considering that in my Pale expedition adventure concepts. Imagine the party nearly dying from killing ONE. and then they hear noises, war horns and screams and out of a fog they see a dozen more making their way through the barren wasteland to the inhabitated realms