A weasel paying a New Year call to a chicken, with no good intentions

A weasel is an enemy of the chicken, often attacking and eating them when it is dark.
If it pays a courtesy call to a chicken during New Year, it sounds strange, doesn't it?
Indeed, it does this not out of kindness or politeness, but with an ulterior motive—to find
an opportunity to catch the chicken and eat it up.
So, never trust the apparent friendliness of a weasel.
In this idiom, the weasel is a metaphor for someone with an evil intention,
and the chicken is a metaphor for someone weak and vulnerable.
This idiom is used to describe someone pretending to be kind and friendly,
but with an evil intention at heart or having an axe to grind.