As the wildlife expert said to the chameleon “you’ve changed”.   That line is what was in my head the moment I woke.  Then I thought  must write that joke down.  But after a
moment I realise that it could not be an original joke, someone must have thought of that joke before.  I could develop it to “As the wildlife expert said to his ex who just happened to be a Chameleon ‘you’ve changed’”. Now that’s getting a little better.  I could develop it further and say “At the end of their stormy relationship the Chameleon said to her boyfriend the wildlife expert ‘no, I’ve not changed. It’s you that’s changed’”.