Gandalf, Party Guest - Intelligence

Gandalf asks for cheap legendary Wizards, enough mana to cast him before combat, protection for the threshold, and high-impact spells that are useful when cast during the combat step.

Gandalf must be present as the beginning-of-combat step starts. Entering later in combat or entering already attacking does not trigger the ability.

The ability does not target. Removing Gandalf after the trigger exists does not remove that trigger.

Calculate X as each trigger resolves. The count is not locked in when combat begins, so adding or removing legendary Wizards can change the threshold.

Count permanents the trigger controller controls that are both legendary and Wizards. Gandalf normally counts himself; nonlegendary Wizards and legendary non-Wizards do not.

Maskwood Nexus or Arcane Adaptation can make legendary creatures Wizards, but they do not make nonlegendary creatures legendary.

The spell is cast from hand during trigger resolution. The permission cannot be saved, and sorceries can be cast during combat because the effect gives permission.

Casting without paying the mana cost is an alternative cost, so overload, flashback, escape, foretell, cleave, and other alternative costs cannot also be chosen.

Optional additional costs such as kicker, buyback, entwine, replicate, casualty, bargain, and spree can be paid when legal; mandatory additional costs are still required.

For an eligible spell with X in its mana cost, X is 0 unless a current rule or effect supplies a different value. Gandalf's threshold is not assigned to the spell's X.

Legal instant and sorcery cards with no mana cost and mana value 0, such as Ancestral Vision, Wheel of Fate, and Restore Balance, can be cast through Gandalf if other restrictions are satisfied.

Only the spell face being cast matters for split cards, fuse, Adventures, modal double-faced cards, aftermath, prototype, and legendary sorceries.

Each additional combat on Gandalf's controller's turn creates another beginning-of-combat trigger if the relevant Gandalf object is present as that step begins.

Increase legendary Wizards before adding expensive spells.

Use the threshold table to decide which high-mana-value spells are actually castable.

Double or copy Gandalf's beginning-of-combat trigger instead of only increasing the Wizard count.

Use copy effects and legend-rule bypass cards while tracking whether each copy is legendary.