Is Weakness legal in Standard, Modern, and Commander?

Weakness is legal in: Modern, Legacy, Vintage, Commander, Pauper.

What type of card is Weakness?

Weakness is an Enchantment — Aura. Its oracle text reads: "Enchant creatureEnchanted creature gets -2/-1."

Enchantment — Aura

Enchant creature<br>Enchanted creature gets -2/-1.

Set Limited Edition Alpha

Rarity Common

Artist Douglas Shuler

Enchantment Modern Commander Pauper