My colleague laughed at my iphone case and told me it was childish and stupid?

I ignored her of course and said "i like it" and laughed it off. But everytime she sees it she laughs and makes fun of me in frint of others
Its a blue glitter pattern

Duo

Just don't carry it when she's around and then she won't get a chance to bother you about it

You carry that phone case with pride! You need to prank this colleague! Buy multiples of blue glitter everything and surround her desk with glitter!

And your question?

We each have a different perspective on any given circumstance and while your colleague may choose to laugh at your iPhone case, this does not equate to you being wrong or inferior in any way. You like your iPhone case and that is totally valid for you. Given you can't change other people, focus on yourself and if you truly feel your colleague is crossing a professional boundary, speak to her directly and ask her to refrain from commenting on your iPhone case or speak with your Manager. People who choose to engage in teasing behaviour, usually do so as a way of distracting themselves from their own insecurities/problems and making themselves feel better.

And? Why do you need to pay any attention to her?

As long as you keep reacting, she'll keep being silly. Try ignoring her reaction. It may take some time, but, if you persist, the fun will be gone for her and she'll give it up.