Mirk, Antique Collector

When Mirk is cast from your hand or deals combat damage to a player, you may search a library for an artifact with converted mana cost
5 or less. If you do, exile it, then shuffle the searched library. For as long as that card remains exiled, Mirk gets +X/+X and has hexproof and haste, where X is that card's converted mana cost.
At the beginning of your upkeep, put an artifact exiled with Mirk onto the battlefield under your control.