Teru-sama
From Bulbapedia, the community-driven Pokémon encyclopedia.
Teru-sama (Japanese: カビチュウ Kabichū) is a glitch item that appears in Generation II. It appears to have no other use than to be sold for
19660. It is kept in either the key items case, or the items one. Teru-sama is a data filler between actual items (like Missingno. is filler between Pokémon).
Teru-Sama can literally be translated from Japanese as "Lord Sunshine", coming from the words Teru (Sunshine or to Shine) and the suffix -sama (an honorific that shows extreme respect and is often translated as "lord" or "master").
Despite popular myth, Teru-sama is not the GS Ball; however, the item slot that the GS Ball is programmed into in Pokémon Crystal was an item slot containing the Teru-sama in Gold and Silver, as with the other Crystal-exclusive items (such as the Egg Ticket and Blue Card).
Despite this, it can still be made into a GS Ball if given to Kurt, the Poké Ball researcher and manufacturer, in Azalea Town.
Teru-samas, through hacking, can be actually used. Two Teru-samas are actually usable. One brings up the Town Map. It displays the Kanto map in less than 1/10 of a second, and when returning to the item menu, the tiles become glitched. Another item is the Poké Flute, which works exactly the same as in Generation I, but remains silent.

