Reusable gel packs. These are cold therapy packs which contain a form of gel and are kept in the freezer until required. They are reusable and in many cases can also be heated either in very hot water or a microwave to offer warm therapy instead.
A clown car is a prop in a circus clown routine. A common example of such a routine involves an implausibly large number of clowns emerging from a very small car, to humorous effect.
The party also tweeted an additional comment in GIF form ridiculing his major announcement at the Trump Tower: Ooooh, except that maybe Donald Trump will upgrade the GOP clown car to a Rolls-Royce.