“Nakem” means “revenge” in Hebrew. They planned to poison water mains to achieve their goal, but were thwarted by police. Later, they poisoned thousands of loaves of bread which were actually consumed, resulting in widespread illness, although no deaths are known to have occurred as a result.
It’s a pretty delusional thing - the Holocaust required massive particpation from millions of people and huge state resources to “achieve.” And that’s just the Holocaust, which doesn’t even cover half of the victims the nazis and their enthusiastic European collaborators murdered.