SWSH - Dynamax Crystals
When players purchase the Double Pack for Pokémon Sworld & Shield, they will be given 2 codes (1 per game) that gives them an item called the Dynamax Crystal.
The Dynamax Crystal allows players to participate in a Max Raid Battle and encounter either Larvitar or Jangmo-o.
US source: https://swordshield.pokemon.com/en-us/buy-now/dynamax_crystals_offer/
EU source: https://swordshield.pokemon.com/en-gb/buy-now/
JP source: https://www.pokemon.co.jp/ex/sword_shield/lineup/1907
I have the wonder card, but as the card is not injectable (only the records are), you should:
1. Ensure your console attempted to receive wonder cards
2. Inject the items into your bag.
If your never connected to Mystery Gift servers or is banned (so unable to connect), the items won't work.
edit:
Technical details are.. the descriptions (and usage) of the item is added via the part of the Switch console that stores periodic game update data.
In other words, no game update =