Once an item glimmer is played it remains in your playing field even after it has been exerted, with the only way for your opponent to banish it being through using abilities or other action cards
If you keep playing cats, Arahbo generates more tokens while pumping them
Caesar, Legions Emperor I wanted at least one commander from a Universes Beyond product here because thats part of the reason they exist: to attract new players to Magic through I.P.s that they already know
Similarly, the player, planeswalker, or battle it attacked doesn't have to still be in the game or on the battlefield, respectively
Its one of the best ways to rummage for cards, fill your graveyard with spells, and create a small army of creatures at the same time