What does Unicorn's Horn do in CK3?

Prestige +0.12/month (patch 1.20.0.3).

How do you get Unicorn's Horn with the console?

effect create_artifact_wall_narwhal_horn_effect = { OWNER = root } — runs the scripted effect that makes it, for the character you play (debug mode).

Court artifact · Small Wall Ornament

Unicorn's Horn

Rarity rolled when it is madeThe Royal Court

Unicorn's Horn is a small wall ornament artifact in Crusader Kings III: Prestige +0.12/month. It needs The Royal Court. Patch 1.20.0.3, from game/common/scripted_effects/01_ep1_court_artifact_creation_effects.txt.

Quick answers (2)

What does Unicorn's Horn do in CK3?: Prestige +0.12/month (patch 1.20.0.3).
How do you get Unicorn's Horn with the console?: effect create_artifact_wall_narwhal_horn_effect = { OWNER = root } — runs the scripted effect that makes it, for the character you play (debug mode).

A large, straight horn of glistening white. Rumored to have been taken from the body of a slain unicorn. The horn is … preserved and attached to a … decorated … mount.

Effects

Prestige+0.12/month

Also gets random bonuses when it is made, from add_scaled_artifact_modifier_grandeur_big_effect, add_scaled_artifact_modifier_prestige_effect, add_scaled_artifact_modifier_piety_effect, add_scaled_artifact_modifier_majesty_effect, add_scaled_artifact_modifier_dynasty_prestige_effect — the bigger ones at higher rarity.

History and who has it

discovered for root in province scope:location.

How it is made

The game creates it with the scripted effect create_artifact_wall_narwhal_horn_effect. In the console (how to open it), this gives it to the character you play:

effect create_artifact_wall_narwhal_horn_effect = { OWNER = root }

Built from the effect's file; not run in the game by us.

Source: game/common/scripted_effects/01_ep1_court_artifact_creation_effects.txt, common/modifiers (artifact_monthly_prestige_3_modifier) and the English localisation, Crusader Kings III 1.20.0.3.