Measuring hashtag evolution on Mastodon means focusing on how users riff on language, not just what is posted. Watching repost chains, ironic usage, and sudden context shifts reveals which memes spread or collapse. Tracking engagement spikes or quote-post reinterpretations shows which absurd tags stick. Analyzing repeated corrections or parody spin-offs highlights gaps in cultural recognition. Instead of heatmaps, we read interaction logs of boosts and replies. These signals guide how communities remix humor and structure discourse.