If you don't choose a second target for Cut In, the Young Hero Role token won't be created.

Roles are colorless enchantment tokens. Each one has the Aura and Role subtypes and the enchant creature ability.

If a permanent has more than one Role attached to it controlled by the same player, each of those Roles except the one with the most recent timestamp is put into its owner’s graveyard. This is a state-based action.

If two or more Roles controlled by the same player become attached to a permanent at the same time (perhaps due to an effect such as that of Doubling Season), that player chooses which one to keep and which are put into their owners’ graveyards.

A permanent can have multiple Roles attached to it if each one is controlled by a different player.

Some spells and abilities that create Role tokens require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won’t resolve. The Role token won’t be created.

In rare cases, a spell or ability might attempt to create a Role token enchanting a permanent that it can’t legally enchant (because of an ability like protection from enchantments). In such cases, the Role token isn’t created.

Hexproof and shroud won’t prevent a Role from becoming attached to a permanent if the ability creating that Role attached to that permanent doesn’t target it.

Cut In : règles, fonctionnement et interactions (MTG)

Cut In is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Cut In deals 4 damage to target creature. Create a Young Hero Role token attached to up to one target creature you control. (If you control another Role on it, put that one into the graveyard. Enchanted creature has "Whenever this creature attacks, if its toughness is 3 or less, put a +1/+1 counter on it.")

How it works : Cut In

Original English text — Wizards of the Coast / Scryfall

#1September 1, 2023· Wizards of the Coast
If you don't choose a second target for Cut In, the Young Hero Role token won't be created.
No other card is named in this ruling.
#2September 1, 2023· Wizards of the Coast
Roles are colorless enchantment tokens. Each one has the Aura and Role subtypes and the enchant creature ability.
No other card is named in this ruling.
#3September 1, 2023· Wizards of the Coast
If a permanent has more than one Role attached to it controlled by the same player, each of those Roles except the one with the most recent timestamp is put into its owner’s graveyard. This is a state-based action.
No other card is named in this ruling.
#4September 1, 2023· Wizards of the Coast
If two or more Roles controlled by the same player become attached to a permanent at the same time (perhaps due to an effect such as that of Doubling Season), that player chooses which one to keep and which are put into their owners’ graveyards.
No other card is named in this ruling.
#5September 1, 2023· Wizards of the Coast
A permanent can have multiple Roles attached to it if each one is controlled by a different player.
No other card is named in this ruling.
#6September 1, 2023· Wizards of the Coast
Some spells and abilities that create Role tokens require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won’t resolve. The Role token won’t be created.
No other card is named in this ruling.
#7September 1, 2023· Wizards of the Coast
In rare cases, a spell or ability might attempt to create a Role token enchanting a permanent that it can’t legally enchant (because of an ability like protection from enchantments). In such cases, the Role token isn’t created.
No other card is named in this ruling.
#8September 1, 2023· Wizards of the Coast
Hexproof and shroud won’t prevent a Role from becoming attached to a permanent if the ability creating that Role attached to that permanent doesn’t target it.
No other card is named in this ruling.
#9September 1, 2023· Wizards of the Coast
Cards in the Wilds of Eldraine main set create six different Role tokens: Cursed, Monster, Royal, Sorcerer, Wicked, and Young Hero. A seventh Role token, Virtuous, is created by Ellivere of the Wild Court, the commander of the “Virtue and Valor” Commander Deck.
No other card is named in this ruling.