Gensokyo/Kappa Explorer

The Kappa Explorer is a Hardmode enemy which may spawn in any body of water, except those situated in the Crimson, Corruption or Hallow biomes. She will approach the player while periodically shooting with a Kappa Water Pistol.

Kappa Explorers drop between three and five Point Items, a small amount of Hydro Charge ammunition, and may also drop Broken Kappa Technology, a material used to craft Kappa weapons and the Experimental Transmitter, used to summon Nitori Kawashiro.

The Kappa Explorer counts as a Kappa enemy, thus, killing enough of them (30) will summon Nitori Kawashiro.