Oskar, Deranged Genius

Oskar's power and toughness are both equal to
the number of Artifacts you control.
At the beginning of your upkeep, discard a card.
Each nonland artifact card in your hand without madness has madness. Its madness cost is equal to
its mana cost reduced by {1}. (If you discard that
card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)