0x33's Aviators and developer items are the only Expert mode items that don't have the 12* rarity.
On the Console version, if the player defeats the Eye of Cthulhu, gets its Treasure Bag with a Soft- or Mediumcore character, and then gives it to a Hardcore character, they will still get the aviators.
On the Desktop version and Mobile version, the Eye of Cthulhu's Treasure Bag no longer yields 0x33's Aviators even if it is opened by a Hardcore character. The only way to get this item is by defeating Eye of Cthulhu in Master Mode.
The Aviators are a reference to Terraria streamer 0x33 who killed the Moon Lord in Expert Mode with a Hardcore character.
Its tooltip, "'Great for impersonating streamers!'" is both a reference to 0x33 and to that of developer items, whose tooltips are similar ("'Great for impersonating devs!'").