up to (one's) (old) shenanigans

1. Engaging in the tricks, pranks, or mischievous behavior one is known for. Food went missing from the school cafeteria? It sounds like Billy is up to his shenanigans again. I reunited with my two best friends after nearly five years apart, and we were up to our old shenanigans in no time.

2. Engaging in the deceitful, underhanded behavior one is known for. As the stock market's volatility continues, it seems like the financial institutions responsible for the last economic meltdown are getting up to their old shenanigans again. The notorious hacking group is up to its shenanigans again, this time infiltrating the servers of one of the largest tech companies in the world.