He is quoting Hitler and joking to become a dictator.

https://www.reuters.com/world/us/trump-repeats-poisoning-blood-anti-immigrant-remark-2023-12-16/ - immigrants poisoning blood

https://www.usatoday.com/story/news/politics/onpolitics/2019/05/09/trump-chuckles-shooting-migrants/1150160001/ - shooting immigrants

https://www.businessinsider.com/trump-negotiate-third-term-in-office-2020-9 - Trump wants to negotiate a 3rd term.

president for life sounds good - https://www.youtube.com/watch?v=09ZCJnf-qM