Combo milestones are a specific set of combos that trigger the game to shoot stars and display a comboburst (if enabled in the options). The combo milestones for osu! and osu!catch are 30x, 60x, 100x, and multiples of 50 after 100. For osu!taiko, the combo milestones are multiples of 50. For osu!mania, the combo milestones are multiples of 100.