As part of the outcomes of that quest, Rex can receive different buffs and drawbacks depending on which brain you ultimately jam into him, represented on his card in a pretty slick way by letting him steal the abilities of creatures you exile with his Energy ability
Spellweave also automatically detects combo lines throughout the deck, including interactions you may not have intentionally included, then backs that up with deeper analysis tools that go over strengths, weaknesses, mulligan decisions, and overall gameplan
These cards may be unwanted, having been acquired when buying boxes and booster packs in search of other cards, or they may be old cards that you dont play with anymore as you acquire the newest sets to construct decks
Especially when you risk getting a bad mana base
Chaos: Whenever you roll Chaos, choose target opponent