Based on powerful or Key Items found in the primary handheld games, Summoning Items are used to obtain the eggs for one of thirteen Very Rare Pokémon. Summoning Items may be used in the Lab, after which an egg related to the item used is summoned. Immediately after being summoned, the egg will appear in the lab and, for five minutes, be available only to the summoner. After these five minutes, however, the egg may then be claimed by anyone who sees it. The egg does not necessarily appear right away, though - it is simply inserted into the Lab and will appear at random. Many users who have completed a large portion of their Egg Dex may opt to use a Repel in conjunction with a Summoning Item if they have not yet obtained the data for the egg they've summoned, as it will effectively "block" all eggs except their summon.
As fitting the rarity of the resulting Pokémon, Summoning Items can be obtained from Treasure Chests and the Underground with low encounter rates. A few Summoning Items can be obtained as Achievement or Exploration rewards, and as of September 29, 2011, three are rotated through the Prize Shop every 12 hours and cost 20 Prize Points each. Enigma Stones were soon added to the list of items. Acting as a "generic" Summoning Item, an Enigma Stone will summon a random egg from the 13 summonable eggs. They can also be obtained as the rewards to certain Achievements, and can be purchased from the Prize Shop at any time for 15 Prize Points.
All Summoning Items, including the Enigma Stone, have an "inherent value" of 20,000 points, however, Summoning Items cannot naturally be purchased from the main section of the shop. This value is still used though to determine other prices related to Summoning Items, such as their selling price (10,000 points), and their purchase price in the backroom (15,000 points).