Cheapest priced copy (Theros Beyond Death): $0.35 at Card Kingdom, near mint, their price list as of .
Setessan Skirmisher 
Creature — Human Warrior · 2/1 · Common · Theros Beyond Death · #200
Constellation — Whenever an enchantment you control enters, this creature gets +1/+1 until end of turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Theros Beyond Death | 200 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 24 January 2020A 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.
- 24 January 2020An Aura spell that has an illegal target when it tries to resolve doesn’t resolve and is instead put into its owner’s graveyard. It doesn’t enter the battlefield, so constellation abilities don’t trigger.