That ability is "When the last defense counter is removed from this permanent, exile it, then you may cast it transformed without paying its mana cost."
Or they can be traded in, alongside a resource called Shinedust, for a special flair - essentially a fancy sparkle or themed effect that triggers when you play a card from your hand in a match
Whether that has a shred of truth to it, who really knows besides the artist, sowsow
C Common Salamangreat Spinny X FIRE Level 3 [ CyberseEffect ] ATK 1000 DEF 1500 If you control a "Salamangreat" card: You can discard this card, then target 1 face-up monster on the field
Heres how this continuous trap works: once per turn, when an opposing monster attacks, you toss a coin three times
It shows that in a recent event, they paired Weevil with the much better Inzektor deck rather than these bum bugs