Accumulative Trigger centers on the visual effect of special symbols (like Wilds or Coins) flying into an object such as a treasure chest, pot, basket, or bag located above or beside the reels. The key characteristics are 'Randomness' and 'Visual Suggestion'. While visual cues like a shaking full chest or overflowing coins create a psychological expectation that "it's about to pop," the feature usually triggers based on a random probability on each spin rather than filling a specific quota.