Tablet Fragment

Not to be confused with the Solar Tablet Fragment.

The Tablet Fragment is a pet item which has a 25% chance to drop from the Lunatic Cultist in Master mode. It summons a Phantasm Dragon pet that will follow the player around. It resembles the phantasm dragon spawned during the boss fight, aside from having fewer legs. When the character is fighting Betsy the dragon, this pet will turn red similarly to Betsy.

Trivia

 * Its tooltip, "It keeps looking at the Moon", may be a reference to the final boss, Moon Lord.
 * This item appears to be a part of the Mysterious Tablet.