Mechanics

Evolution Rarity and Legendary Upgrades Guide | Everything is Crab

By Nocti · Last updated

Evolution rarity questions are really draft-timing questions: when to take a useful card now, how the 10-Mutagen rarity upgrade works, when to hold points for a later jump, and how Patient or Ambivalent change the odds.

Practical use

  1. Current June 2026 public discussion points to the same practical rule many strong runs already follow: if an evolution is core to the route, take the usable version first instead of dying while waiting for the perfect color.
  2. A September 19–20 Steam exchange describes the upgrade control on the Evolution choice screen: spend 10 Mutagen to raise the current offers by one rarity tier. Players identify this as the action used for Elitist's 20-upgrade achievement, but the thread does not establish whether progress is counted per purchase or per offer shown; use the in-game counter.
  3. Patient matters because skipped level-ups improve the next evolution's rarity chance until a pick is taken, so the gene is strongest when you already know which breakpoint card you want.
  4. Ambivalent retains its size-based rarity trait and, since Version 1.1, also multiplies Mutagen gains for small builds. Choose size-changing evolutions according to the benefit your route needs.
  5. A later rarity upgrade appears to overwrite the current tier of that evolution, so legendary planning is most valuable on the final meaningful level of the card rather than every early click.
  6. Do not spend mutagen chasing rarity while food, movement, or boss-safe damage are still unsolved; a complete shell beats a shiny incomplete one.

Rarity planning checkpoints

QuestionShort answerUse it this way
What does an upgrade mean for Elitist?Spend 10 Mutagen on the upgrade option shown with the current offers.The September exchange identifies this rarity purchase as the achievement action, but not whether progress counts the purchase or each offer shown; track the in-game counter.
Should I skip a useful card because it is not legendary?Usually no.Take the route piece first when the run still needs food, movement, or safe damage.
When is Patient strongest?When you already know which breakpoint card you want next.Spend skips near meaningful level-up checkpoints instead of skipping blindly.
How does Ambivalent use size?It supports both size directions.Large-body rarity and the Version 1.1 small-body Mutagen multiplier serve different goals. Check which benefit your size choices support.
When is rarity worth holding mutagen for?Near the final meaningful level of a core evolution.Late upgrades matter more than coloring every early level.
What should beat rarity greed?A complete shell.If the build still lacks food, movement, or boss-safe damage, solve that first.

The current public discussion is useful because it turns rarity from a mystery into a drafting question: card timing, not only card color.

Related pages

Beginner First Clear

Plan a Pressure 1 attempt around the cards you can use: reach food, escape dangerous attacks and develop one reliable attack. Compare alternatives before committing upgrades.

Read guide

Physical Predator

Direct-contact damage, meat routing, and Physical scaling for players who want bosses to end quickly instead of becoming endurance checks.

Read guide

Poison Trickster

Choose a way to apply poison, then build around the openings needed to use it. Compare Spit with Poisonous Saliva, Stinger, and the conditional Pedal Glands route without treating every card as mandatory.

Read guide

Compare rarity and level separately in the Codex

This also gives a practical way to budget around a specific card. Identify the next effect you want, then compare the displayed versions of that Evolution. A desire for a Legendary label is not itself an explanation of which part of the route improves. If the relevant change belongs to a specialisation or a later level, a rarity purchase should not be assumed to grant it automatically.

FAQ

How can I compare rarity and level without mixing them up?

Version 1.2 expanded the Evolution Codex so players can inspect the stats at all rarity tiers and levels. Use that view before deciding that an upgrade has lost an effect or that two screenshots show the same card. A later level at one rarity is a different comparison from the same level at a higher rarity; keep both labels in the comparison.

Source

Three choices that look similar but have different rules

FAQ

Does levelling an existing Legendary trigger Elitist’s new-Legendary reward?

Buying a rarity upgrade, acquiring a new Legendary Evolution and levelling an existing Legendary Evolution are separate events. Version 1.2 makes this distinction explicit for the Elitist Genetic: acquiring a new Legendary Evolution grants an immediate level, while upgrading an existing Legendary to level two or higher does not trigger that benefit. A new Common Evolution carries the separately described Max HP penalty.

Can Chosen bypass a branching Evolution’s requirement?

Chosen changed in the same update. Its offer contains three new Legendary Evolutions, excluding upgrades and branching Evolutions. If your plan requires a specific branch, neither the word Legendary nor Chosen’s starting effect establishes a way to skip that branch’s requirement. Read the type of choice as carefully as its color.

Source

Update history

: Added the all-tier Codex view and distinguished rarity purchases, new Legendary acquisitions and later levels. Explained the separate Elitist triggers and Chosen offer exclusions.