Troll bot 

A paid online actor who dispells false propaganda, ad hominem attacks , or changes the subject as a distraction during online discussion usually in regards to politics or current events

Don: What's going on with my Twitter account - all these crazy posts ! ?

Kelly ann : Wow. Okay... It looks like that troll bot is hard at work today.

Troll bot by tjamnz March 25, 2019

bottom feeder troll 

a troll that feeds off of the trolls that troll the trolls

Go back to your little hole, you bottom feeder troll.
He/She is a bottom feeder troll.

bottom feeder troll by theincubator August 17, 2021

trollbot 

1) The opposite of a fanbot, except unlike fanbots, trollbots have often not even experienced the game or service in question, they just automatically adopt an intensely negative position based on personal bias and ignorance.

2) Someone who hangs around game forums posting unimaginative negative disinformation or flamebait that is not backed up by evidence or experience.

"this game is a scam"
"stfu trollbot"

trollbot by wowwhatacunningstunt2 July 24, 2009