Coins of the Underworld are shaped from clay funerary masks.

Underworld Coinsmith

Constellation — Whenever this creature or another enchantment you control enters, you gain 1 life.
{W}{B}, Pay 1 life: Each opponent loses 1 life.

The List

Commander 2015

Constellation — Whenever Underworld Coinsmith or another enchantment enters the battlefield under your control, you gain 1 life.{W}{B}, Pay 1 life: Each opponent loses 1 life.

Journey into Nyx

Constellation — Whenever Underworld Coinsmith or another enchantment enters the battlefield under your control, you gain 1 life.
{W}{B}, Pay 1 life: Each opponent loses 1 life.

A constellation ability triggers whenever an enchantment enters the battlefield under your control for any reason. Enchantments with other card types, such as enchantment creatures, will also cause constellation abilities to trigger.

An Aura spell without bestow that has an illegal target when it tries to resolve won't resolve and will be put into its owner's graveyard. It won't enter the battlefield and constellation abilities won't trigger. An Aura spell with bestow won't be countered this way. It will revert to being an enchantment creature and resolve, entering the battlefield and triggering constellation abilities.

When an enchantment enters the battlefield under your control, each constellation ability of permanents you control will trigger. You can put these abilities on the stack in any order. The last ability you put on the stack will be the first one that resolves.