You gain a +3 bonus to attack and damage rolls made with this magic vorpal sword. In addition, the weapon ignores resistance to slashing damage. When you use this weapon to attack a creature that has at least one head and roll a 20 on the attack roll, you cut off one of the creature's heads. The creature dies if it can't survive without the lost head. A creature is immune to this effect if it is immune to slashing damage, it doesn't have or need a head, it has legendary actions, or the DM decides that the creature is too big for its head to be cut off with this weapon. Such a creature instead takes an extra 6d8 slashing damage from the hit.
While attuned to Snicker-Snack, you have proficiency with greatswords, and you can use your Charisma modifier instead of your Strength modifier for attack and damage rolls made with the weapon.
Snicker-Snack is a sentient, chaotic good greatsword with an Intelligence of 9, a Wisdom of 14, and a Charisma of 18. It has hearing and darkvision out to a range of 120 feet. It can speak, read, and understand Common, and its voice sounds silvery and melodic. Snicker-Snack craves the destruction of evil Dragons and urges you to seek out these creatures and slay them.
Snicker-Snack has a fickle personality. It ends its attunement to you if you miss on attack rolls with the weapon three times in a row. Each time you finish a long rest after that happens, you can attempt to regain the sword's trust by making a contested Charisma check against Snicker-Snack. If you win the contest, your attunement to the weapon is instantly restored. Your attunement to the weapon can't be restored in any other way.
Creatures that are Small or Tiny have disadvantage on attack rolls with heavy weapons. A heavy weapon's size and bulk make it too large for a Small or Tiny creature to use effectively.
This weapon requires two hands to use. This property is relevant only when you attack with the weapon, not when you simply hold it.