Word for two very particular phrases

So I remember seeing a really specific Wikipedia (I think) page describing an odd occurrence in English. It was used to describe two idioms that mean the same thing, but are phrased differently due to people misinterpreting the statement.

For example, 'All intents and purposes' and 'All intensive purposes'.

If anyone knows the phrase, or possibly even a similar phrase that could lead me to my answer, please share.

Thank you!

You say ...

...used to describe two idioms that mean the same thing ...

'All intents and purposes' and 'All intensive purposes'

However those don't 'mean the same thing'.

You might be thinking of mondegreens

A mondegreen /ˈmɒndɪɡriːn/ is a mishearing or misinterpretation of a phrase as a result of near-homophony, in a way that gives it a new meaning. Mondegreens are most often created by a person listening to a poem or a song... https://en.wikipedia.org/wiki/Mondegreen