Idiom request for describing someone who just makes frustrating or disappointing remarks [duplicate]

I'm looking for an idiom or expression that means someone just makes frustrating or disappointing remarks.

Maybe some of you have watched the TV cartoon 'The adventures of Gulliver' in which there was as a character named "Glum". He was all the time pessimistic about everything and used statements like:

"We'll never make it"; "We'll never get out of here alive"; and "We're doomed."

I want to use that idiom or expression in examples like this:

Husband: After getting my promotion, I will take you to a fantastic trip.

Wife: Oh, stop talking nonsense! I know It won't never happen, it's impossible you get a promotion.

Husband: You remind me of 'Glum'! All the time _____ (i.e. acting like Glum, just having a gloomy outlook on everything). Please stop using such remarks and be a little optimistic!

I have found wet blanket for describing such people.

PS:

We Iranians use an expression that literally says "to read a frustrating or disappointing verse".

So in above example, the husband might reply like this:

Hey Glum, the only thing you know is reading a frustrating/ disappointing verse!

(Sometimes we call these people 'Glum'.)

Solution 1:

I've got a gut feeling that this question is a duplicate, but "naysayer" fits in your context:

a person who habitually expresses negative or pessimistic views: 'Despite a general feeling that things were going well, a few naysayers tried to cast gloom.

[Dictionary.com]

Solution 2:

You could call them a Debbie Downer

It is a slang phrase which refers to someone who frequently adds bad news and negative feelings to a gathering, thus bringing down the mood of everyone around them.

It's also a character from Saturday Night Live, portrayed by Rachel Dratch.

Solution 3:

Buzzkill — ODO

US, informal A person or thing that has a depressing or dispiriting effect
"if you think bad weather at the zoo sounds like a buzzkill, you’re right"

Killjoy — ODO

noun A person who deliberately spoils the enjoyment of others
"a few killjoys try to reform the seasonal activities"

Spoilsport — ODO

noun A person who behaves in a way that spoils others' pleasure, especially by not joining in an activity
"Don’t be a spoilsport, Sidney."