Incite Hysteria

• WWizards of the Coast2005-10-01
  Official Ruling
  All creatures that share a color are affected, even your own.
• WWizards of the Coast2005-10-01
  Official Ruling
  Only one creature is targeted. If that creature leaves the battlefield or otherwise becomes an illegal target, the entire spell doesn’t resolve. No other creatures are affected.
• WWizards of the Coast2005-10-01
  Official Ruling
  You check which creatures share a color with the target when the spell resolves.
• WWizards of the Coast2005-10-01
  Official Ruling
  A creature “shares a color” with any creature that is at least one of its colors. For example, a green-white creature shares a color with creatures that are green, white, green-white, red-white, black-green, and so on.
• WWizards of the Coast2005-10-01
  Official Ruling
  If it targets a colorless creature, it doesn’t affect any other creatures. A colorless creature shares a color with nothing, not even other colorless creatures.
• WWizards of the Coast2005-11-01
  Official Ruling
  The targeted creature and the creatures that share a color with it at the time Incite Hysteria resolves gain an ability that says they can’t block this turn. It doesn’t matter if those creatures change colors before blockers are declared.

Rulings via Scryfall