Haktos the Unscarred

Haktos attacks each combat if able.
As Haktos enters, choose 2, 3, or 4 at random.
Haktos has protection from each mana value other than the chosen number.

Magic Online Promos

"Many have sought my weakness. All have failed."

Theros Beyond Death Promos

Theros Beyond Death

Haktos the Unscarred attacks each combat if able.
As Haktos enters the battlefield, choose 2, 3, or 4 at random.
Haktos has protection from each converted mana cost other than the chosen number.

A number is chosen randomly for Haktos before it enters the battlefield. There's no point at which players can target it before it has gained the appropriate protection abilities.

For spells with {X} in their mana costs, use the value chosen for X to determine the spell's mana value. If a card or permanent in any other zone has {X} in its mana cost, X is considered to be 0.

Haktos has protection from each possible mana value other than the chosen value, not just protection from the two options that weren't randomly chosen.

If Haktos can't attack for any reason (such as being tapped or having come under that player's control that turn), then it doesn't attack. If there's a cost associated with having it attack, you aren't forced to pay that cost, so it doesn't have to attack in that case either.

If Haktos somehow has no choice made for its ability, its last ability grants it no protection abilities.

The mana value of a token that isn't a copy of another object is 0. A token that is a copy of another object has the same mana value as that object.