There was a genuinely "left-wing" part of the Nazi party (Strassurists)[1], though they along with their leader (Ernst Rohm)[2] were purged in the night of the long knives (also known as the Rohm purge)[3]

The Germans had a term for communists who swapped to the Nazi party - Beefsteak Nazis[4]. Brown on the outside and red on the inside.

1. https://en.wikipedia.org/wiki/Strasserism

2. https://en.wikipedia.org/wiki/Ernst_R%C3%B6hm

3. https://en.wikipedia.org/wiki/Night_of_the_Long_Knives

4. https://en.wikipedia.org/wiki/Beefsteak_Nazi