The Square Tire is an offensive Item exclusive to the long item lists of the Mario Kart Arcade series. This Throw forward power-up strikes its victim with tedious, edgy tires that make it hard to drive.
It is yet to be known whether or not it's in the latest arcade installment, Mario Kart Arcade GP VR.
Like many of the Throw forward Items from the Mario Kart Arcade lineup, the Square Tire locks onto the opponent directly in front of the user's Kart. Hitting the item button fires the tire, and upon impact, the opponent's wheel's become square shaped. As you can imagine, controllability is at a low with blocks for wheels, in this effect can last for up to 20 seconds, making it a very sweet Item to receive from the Item roulette.