Salami attack is for

A salami attack (also known as salami slicing) is a series of minor, almost unnoticeable data modifications or thefts that collectively add up to a significant amount over time. The name comes from the analogy of slicing a salami sausage so thinly that no one notices a single slice is missing, but eventually, the entire sausage is gone.

In the digital world, this is almost exclusively used for financial crimes and fraud.