Mothers-in-law often have a bad reputation but in this case it's justified.
A new mum wrote anonymously to 'Care and Feeding', the parental advice column in online magazine Slate, describing her horror tale.
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The woman, going by the nickname Mama Bear says she was asleep and recovering from her C-section when her mother-in-law changed the middle name of her newborn son from 'Finley' to 'Finlay'.
In her letter, she explained that the deception all happened "over the phone".
"She tried to convince him to give our son a first name that I very much hated, saying that I would "get mad, but get over it'," she wrote.
"My husband thought changing his first name was too much but apparently gave in to spelling his middle name the way his mother wanted."
The mum only discovered his lie when their son was two-months-old and she was filing his birth certificate away.
She said her mother-in-law even sent a Christmas gift addressed to "Finlay", which she thought was a mistake, but says she now believes to be "a manipulative jab".
"His mother has always been a manipulator and I have always known she doesn't like me. But she blatantly disrespected me and the name my husband and I had chosen for our son."
The parenting advice expert behind 'Care and Feeding' didn't mince words with their response.
"What in the entire f**k is up with your husband?" they wrote.
"He's got to decide if you are his co-parent or if his mother is."
Commenters online have expressed outrage on Mama Bear's behalf, calling the move "so shady".
"That's so beyond wrong," wrote one commenter.
"Shameful on both accounts," wrote another.