The Rani
Legendary Creature — Time Lord Scientist, {1}{U}{B}{R}
Oracle Text
Whenever The Rani enters or attacks, create a red Aura enchantment token named Mark of the Rani attached to another target creature. That token has enchant creature and "Enchanted creature gets +2/+2 and is goaded."
Whenever a goaded creature deals combat damage to one of your opponents, investigate.