My girl cat was (I thought) mellow, but when we introduced our terrorist she decided that meant she had free reign to join in and do anything too.
Our terrorist is 5 years old and she’s maybe 6 months or a year older than him.
He growls, plays crocodile from hiding spots, opens cabinet doors, taught himself to break child locks to get into cupboards, opens the freezer to help himself to frozen meat, will eat anything (Spinach! He likes spinach!), regularly has zoomies, will drag his leash/harness over to you when he wants to go for a walk, and has the loudest purr in the world. He loves being carried like a baby and getting belly rubs, jumps on your lap as soon as you sit for snuggles, and does the ‘puss in boots’ look if he gets in trouble. Love him. 