A symbol that substitutes
A wild often substitutes for some ordinary symbols when the game checks a match. It may have restrictions, appear on particular reels or be part of a temporary feature. The game's own panel tells you what it can replace. Its appearance does not mean every visible position becomes a winning match.
A symbol with another job
A scatter is commonly used for a feature trigger rather than an ordinary left-to-right match. The required count and behaviour are game-specific. Some titles use other special symbols or feature names entirely. Check the relevant description rather than carrying the rules from the last game into the next.
A preview is a demonstration
Seeing a special symbol in an animated preview does not predict the next live round. Previews are labelled demonstrations and use no credits. Features in live games follow the actual game rules; neither the mascot nor the site's game selection buttons can cause one to appear.