Water

According to the TSA frozen water is allowed past so long as it is totally frozen and not slushy and has no water at the bottom of the container. Basically make sure it's really damn cold before you leave and hope it doesn't melt on you.

She's right, its a solid

You can also take an empty bottle and fill it after passing through security...

I’ve asked the TSA dudes while going through security this exact question and they confirmed that, yes you can take fully frozen water bottles through security.

You can also just read on their website that, as long as it’s fully frozen when you’re at the security screening, you’re fine. https://www.tsa.gov/travel/security-screening/whatcanibring/items/ice

Creative solution!

Sweet, then I can pre-boil water the day before, freeze it down and bring it on a plane, so that I have boiling water mid flight.

Why were liquids then be banned in the first place?