Sharkey, Tyrant of the Shire I actually really like Sharkey, Tyrant of the Shire, and I think it could lead to some very unique gameplay situations
If you are not sure what to buy, start with Play Boosters
First of all, you get a free almost-Impulse, which lets you sculpt your hand to your current needs
It was certainly a broken mechanic that led to a mechanic-wide errata that wasnt enough to keep multiple companions from being banned in multiple formats
The default best choice is usually their Cranial Plating, their Ensnaring Bridge, their Collected Company, or so on
You can put it in a high mana value commander as a backup win condition, but it really isn't a good idea