Need to summon a kraken? Or have a word with Poseidon? Or simply let the kids know it's time for more sunscreen.

This conch horn is made from a 3d scanned conch shell. The inside was hollowed, and the internal swirl added so that it sounds almost like the real thing. Finally, a trumpet mouthpiece was merged on top. 

This fits an Ender 3 print bed after shrinking the margins a bit – prints as two pieces, Conch_horn_top and Conch_horn_bottom. Also included is a version with a wider mouthpiece.