na-adjective, noun which may take the genitive case particle 'no', noun
extremely rare; super rare
Colloquial intensifier used for things that are very uncommon or hard to find, often in casual conversation about collectibles, events, or opportunities.
このカードは激レアだから、なかなか手に入らない。
This card is super rare, so it's hard to get.
激レアな体験ができて嬉しい!
I'm happy I got to have such an extremely rare experience!