This item is just a plain grey rock nothing special nothing amazing until closer inspection aha! It's a magical bland grey rock this rock has abilities that other rocks certainly don't have 

With 5 rounds of concentration you can cast one ninth level spell (you can only cast one every week) in turn for 5 more rounds of incapacitation (10ft crawling is as much as you can muster) no bonus actions may be taken during this time

A secondary option is to summon a Caucasian tanned bald man who goes by what he comes from this ex wrestler will scream he's cooking when he is summoned frightening even the strongest willed people this unbelievable hunk of a man has 30 strength and Constitution 20 on the rest, he only uses his bulging fists to fight truly breathtaking

(DM will have to decide on health and the rest depending on your current situation)