The cat gargoyles weren’t big enough, but I ordered the cat gargoyle door knocker. We needed one anyhow and we both liked that one. Thanks so much for the link!
Maybe something from Etsy?
(not a bust) Cthulhu - the Great Old One
And absolutely not what you’re looking for, but if I had the yard: Kraken
Yet another vote for same type but different pose. Their being identical just gives the sense that they are lifeless ornamentation. Making them slightly different gives them character.
Whatever you get should incorporate a solar panel and glowing red eyes. An unearthly shriek based on motion detection would be overdoing it.
Depends on how much “blood” sprays out along with the shrieks. Enough blood can make up for almost any statuary shortcomings.
I found it at a vintage market, I actually wasn’t aware of “ball gagging” at the time. A precocious teenager enlightened me. 
Finally uploaded a picture of the neighborhood trolls
How fun, thank you!
Where are you putting the cauldrons of boiling oil?
On the roof of course. You can’t pour that, nor flaming pitch, down on your invaders from anywhere else.
Kids: Trick or treat!
Me: (Heavy French accent) Invaders!
Love it. Off to see the film again. 
I think I whooshed myself. Which film are you referring to?
Monty Python and the Holy Grail, scene at the castle.
Fetchez la vache!
So, what’d you wind up getting, Ms. O.P.?
I suggest buying concrete molds.
Buy a bag of Quikcrete at Home Depot. Add water, mix well, and pour.
Why pay a ridiculous fee plus shipping for already made decorations? A bag of Quikrete is less than $10.
There’s a nice selection of molds.
Of course, silly me. However, groove on this:
When I read LSLGuy’s response, I got to, “Invaders,” and heard it in a heavy French accent. Thought it might be Holy Grail, but it’s not there. Turns out I was thinking Jerry Orbach as Lumiere from Disney’s animated Beauty and the Beast. He hollers that as the villagers are stoimin’ da kestle, which would have been a great place to have boiling oil poured on them. And the circle closes.
If you buy molds make sure the seller provides instructions.
It’s almost foolproof and easy. You do have to clamp and support the mold. Concrete is heavy and the mold could pop open if its not supported.
I did projects like this in Junior high, Industrial Arts class. We used molds to make decorative concrete flower planters.
For more humorous molds, garden “art” there’s TEMU and:
https://www.amazon.com/Funny-Garden-Statues/s?k=Funny+Garden+Statues