This talk will give a tour about PHP Internals. It'll take the audience on a journey from the design behind a custom PHP fuzzer, to how PHP internal heap can be exploited. It will also cover some of the changes in PHP 7 Internals and what that means from an exploit dev perspective. A sample of interesting and unusual PHP bugs that I had discovered will also be presented. I hope to be able to share what had worked for me and what are some of the lessons I've learnt throughout this journey.