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Kelvin Catalyst
  • Kelvin Catalyst.png
Stack digit 1.png
Damage60 Rogue
Knockback4 (Weak)
Critical chance4%
Use time29 Average
TooltipThrows an icy blade that splits into multiple ice stars on enemy hits
Stealth strikes will briefly gain sentience and ram nearby enemies before returning to the player
Inflicts DebuffFrostburnFrostburn
100% chance

Debuff duration4 seconds
1 second (Ice stars)
Debuff tooltipIt's either really hot or really cold. Either way it REALLY hurts
RarityRarity Level: 5
Sell 7 Gold Coin.png 20 Silver Coin.png
Projectile created
Kelvin Catalyst Star
Mini Ice Star

A demonstration of the Kelvin Catalyst being thrown. Note how the ice shards summoned by hitting each enemy only home in on the Super Dummy when the blocks become actuated.

The Kelvin Catalyst is a craftable Hardmode boomerang that does rogue damage. It inflicts the Frostburn debuff and multiple boomerangs can be deployed at once, with the boomerang returning to the owner after a set distance, and breaking upon contact with a solid block. Upon contact with an enemy, the boomerangs spawn eight ice stars each, which do one sixth of the boomerang's base damage, sharply home-in onto enemies, and go through tiles. If no enemies are nearby, the ice stars will shatter. There can only be up to 32 ice stars at a time.

Performing a stealth strike with the Kelvin Catalyst will cause the next boomerang thrown to ram towards the nearest enemy instead of returning to the player, and will return to the player 1 second later.

Its best modifier is Flawless.



Crafting Station
Ice MachineIce Machine
Ice StarIce Star100
Effluvium BowEffluvium Bow1
Glacial CrusherGlacial Crusher1
Snowstorm StaffSnowstorm Staff1
Essence of EleumEssence of Eleum10
Kelvin CatalystKelvin Catalyst1


  • The ice stars deal typeless damage and cannot deal critical hits.
  • Most of this weapon's materials can be obtained from Cryogen. The only exceptions are the Ice Stars, which are bought from the Archmage NPC who spawns after Cryogen is defeated
  • This weapon is extremely effective in early to mid-Hardmode, as it can tear through most bosses at that stage of the game with its high DPS.


  • A catalyst is a substance which increases the rate of chemical reaction but is not consumed upon reacting, thus it can react repeatedly.