Amulet of the Black Skull

From Tomb of Annihilation, page 206.

Description
Wondrous item, very rare (requires attunement).

This amulet is carved from obsidian and shaped like a screaming humanoid skull, with ruby eyes and emeralds for teeth. It hangs from an iron chain necklace.

The amulet has 6 charges and regains 1d6 charges daily at dawn. While wearing the amulet, you can use an action to expend 1 of its charges to transport yourself and anything you are wearing or carrying to a location within 100 feet of you. The destination you choose doesn't need to be in your line of sight, but it must be familiar to you (in other words, a place you have seen or visited), and it must be on the same plane of existence as you. This effect isn't subject to the magic restrictions placed on the Tomb of the Nine Gods; thus, the amulet can be used to enter and exit the tomb.

If you aren't undead, you must make a DC 16 Constitution saving throw each time you use the amulet to teleport. On a failed saving throw, the black skull cackles as you are transformed in transit. The transformation takes effect as soon as you arrive at the destination, and is determined randomly by rolling percentile dice and consulting the Black Skull Transformation table.