The Smasinator is an Advanced Thief type Trap Room card introduced in Boss Monster: The Next Level
The nature of the effect of this card is interesting. If built early on, it can deal with any and all Ordinary Heroes sent its way, as upon activating its effect, The Smasinator can deal 9 damage.
A good strategy for this card, albeit one long, if not hard, to set up, would be to build multiple room stacks and then build this card, and activate it when needed, As this card destroys any VISIBLE Room cards, any rooms uncovered by the Smashinator will not be destroyed. Also, due to the wording, a player could be able to place a card face down during the Build Phase, ready to be built, and then activate Smashinator's effect, and the card yet to be built would be safe from this card's effect, and it could then be built by the end of the Build Phase.
This card seems to follow a pattern of Thief Trap Room cards that act like a brand of killing products. Other examples include the Decapitator and the Crushinator.