Largest living Cell

There exists a single celled organism that can grow to about the size of a golf ball and sometimes bigger. It is a single celled algi called 'Valonia Ventricosa'. It is considered to be one of the largest single celled organisms in the world. 

Picture drawn by AI on behalf of the blog author 

These gigantic single celled organisms can be found in every ocean in the world. They're believed to be able regenerate if they're damaged or broken into multiple pieces. Each fragment could grow into another complete 'Valonia Ventricosa'.