Babe could be seen mocking her sister about her abusive ex-husband Stan and making her feel guilty about walking out on her children.
Sylvie started to tease Babe (played by Annette Badland) about her weight as a teenager, laughing that she couldn't sneak out of their house because she was "too fat" to crawl out of the window.
Unfortunately, her comments struck a chord with Aunt Babe, who then took her out to a nearby canal and pretended to a confused Sylvie (Linda Marlowe) that they were going to meet Stan.
Babe told her that he was waiting for her across the canal and all she had to do was swim across.
The scene then cut to the soap villain arriving at the Queen Vic alone, leading many viewers to speculate that Sylvie had drowned.
Sylvie Carter arrived at the Queen Vic after she was dumped at the canal by Aunt Babe
Sylvie Carter was scared by Aunt Babe when she returned to the pub
Fortunately, Mick's (Danny Dyer) grandmother was found by the canal and taken to a police station. She later arrived at the pub much to the surprise of Babe.
When Babe's plan to murder her sister was revealed to the pub, Mick and Shirley (Linda Henry) wasted no time in kicking her out.
But, while she was finally shown the door, many of those tuning in hit out at the BBC soap for its "disturbing" dementia abuse storyline.
One viewer tweeted: "Well if babe has pushed her in the canal I will never watch eastenders again, horrendous portrayal of dementia #eastenders #angry #soangry."
Annette Badland plays Aunt Babe in the BBC soap
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I will never watch eastenders again, horrendous portrayal of dementia
While another added: "My grandmother suffers from dementia and I am finding this eastenders storyline a little insulting and kind of disturbing tbh #eastenders (sic)."
"#Eastenders are doing a bit far with this storyline… this character has dementia it's disturbing to watch," a third wrote.
Someone else continued: "#eastenders I hate pig woman Its really uncomfortable watching her mentally / physically abuse a vulnerable dementia suffer. Even in a soap."
A fifth shared: "Omg Babe is evil treating a person with dementia like that. Disgusting! @bbceastenders #Eastenders."
EastEnders viewers took to social media to slam the storyline
But, while viewers hated Aunt Babe, many praised Annette for her portrayal, with one viewer tweeting: "Aunt Babe is the child of Satan but the actress who plays her deserves all the awards for that performance #Eastenders."
And another adding: "I hope #AnnetteBadland wins a award for playing #AuntBabe, she's a cracking actress.
Express.co.uk has contacted a representative for EastEnders for comment.