The design is a reference to the Sea Eater. And I created an entire creature just for this drawing... He is completely blind which makes him hunt by sounds and using his tail which in the end has a human shape to attract prey. It is so heavy that it can barely move and that is why it attracts prey instead of hunting, its arms are only used to catch the prey when it falls for the bait on its tail or to help it move.
And yes, the tail imitates human sounds to try to attract them more easily, but it is not a perfect imitation.
Its interior is fragile, so a missile could very well do the job and it wouldn't be that hard to miss with a mouth like that.
And he just tries to imitate the human sounds and voices he hears, whether it's from prey or survivors. But he's not stupid, if there's a group of people he might try to imitate the voice of one of them to get the attention of the rest.