That is a very subjective question, as different people may have different criteria for what makes a president crazy.
However, there are some presidents who have done or said some very strange or controversial things that could be considered crazy by some standards.
Here are some examples:
- Zachary Taylor, who died after eating too many cherries and iced milk, which caused a severe stomach infection1.

- Richard Nixon, who plotted to assassinate a journalist who criticized him by poisoning his medicine cabinet or exposing him to LSD2.

- Andrew Jackson, who taught his parrot to swear and had to remove it from his funeral when it started cursing loudly2.

- Lyndon B. Johnson, who gave interviews from the toilet and urinated in public2.

- Ronald Reagan, who claimed he had filmed the atrocities of the Nazi death camps while serving as a US Army photographer in Europe, which was not true1.

Of course, these are just some of the craziest things that some presidents have done or said. There may be other examples,
To amplify information: