Moon Lord Legs

These only generate in Drunk and Zenith worlds, and when they do they turn up in ordinary chests of any type, dropped in alongside whatever loot that chest had already rolled. Nothing is displaced to make room. That means you can be wearing them within minutes of spawning, long before you could craft anything comparable, and the boss they are named after is nowhere near the picture.

The movement speed boost dwarfs an Aglet several times over. The jump changes are the bigger deal though: they lift both the height and the duration of a jump, which together push your reach up by a large margin over a bare character, and they extend how far you can drop without hurting yourself. On top of that the defense alone matches an entire suit of wood while occupying one slot.

The trick is finding armor whose set bonus does not care about the leg slot. The Wizard Hat family is the obvious partner for an early mage, since those bonuses come off the hat and robe, and the combination can outperform Meteor or Jungle armor for a while. Rain armor has no leg piece to give up at all. Wood-tier and copper-tier sets lose almost nothing by swapping the greaves out and several of them come out ahead on defense. From Iron Greaves upward you start paying for it, though a Shackle covers the gap there and the bars you save cover a pickaxe and a sword. Lead and above cost more than they are worth.

Once Hermes Boots, a Cloud in a Bottle and a decent hook are in your accessory slots, the mobility here stops being special while the defense you are giving up on real armor keeps growing. That is the point to retire them.

If you want your original armor's look back, drop the greaves you replaced into a social slot. The tentacles came from a running community gag about the Moon Lord having no legs, which Redigit answered by adding them as pants rather than as a boss, and the tooltip suggesting they belong to Steve nods at another joke about the Moon Lord's name.