Slay the Spire 2 Byrdonis Egg — Hatch, Byrdpip & Byrd Swoop

Published 2026-09-205 min read

How the Byrdonis Egg works in Slay the Spire 2: where the quest card comes from, how to hatch it at a rest site, and what the Byrdpip relic gives you.

The Byrdonis Egg is Slay the Spire 2's most famous quest card: an unplayable egg that sits in your deck, hatches at a rest site, and hatches into a bird that fights for you. It's also one of the most-searched objects in the game — here's the complete chain, from nest to Byrd Swoop.

The Byrdonis Egg quest card art in Slay the Spire 2
A speckled egg in a burning nest. What could go wrong.

What the Byrdonis Egg card does

  • Type: Colorless, Quest card — Unplayable, cost -2, cannot be upgraded
  • Effect: none while unhatched — except adding a Hatch option to Rest Sites
  • Deck impact: it counts as a dead card until hatched, which is why the deck building math says hatch it at your first safe campfire

Where the egg comes from

The egg comes from the Byrdonis Nest event, tied to the Byrdonis elite — the 81–84 HP Territorial bird elite of the Overgrowth zone (see the boss and elite list). Taking the egg from the nest adds the Byrdonis Egg card to your deck and starts the hatching timer.

How to hatch it (and what you get)

  1. Reach any Rest Site with the egg in your deck.
  2. Pick Hatch instead of Rest or Smith.
  3. You receive the Byrdpip relic — and every copy of Byrdonis Egg in your deck instantly transforms into Byrd Swoop.

Byrdpip is an Event relic: "Upon pickup, gain the card Byrd Swoop. A Byrdpip will accompany you in battles." The little bird follows you through fights — purely cosmetic company, mechanically the value is the card.

Byrd Swoop: is the card good?

Byrd Swoop is a 0-cost Colorless Event Attack that deals 14 damage (18 upgraded) — a free damage card for a free pickup, and unlike the egg it's playable. The economics are simple: you traded one rest-site action and (temporarily) one dead card slot for a free attack card and a pet. On runs where the rest site wasn't needed for healing or an upgrade, that's free value; skip the egg if your HP is already desperate — the rest-site math always outranks the bird.

Tips for the egg run

  • Hatch early. The sooner the egg transforms, the more fights Byrd Swoop pays for itself.
  • Multiple eggs = multiple Swoops. Every copy transforms on hatch.
  • Don't confuse Byrdonis (elite) with the egg. Killing the elite doesn't hatch the egg — rest sites do.
  • Co-op note: quest cards are per-player, so in multiplayer only the egg's owner gets the Hatch option.

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