Chuchu is an enemy type in Hyrule Warriors: Age of Calamity.
Attack moves and how to defeat: They bounce. You hit them. They explode.
If they're elemental (in other words not blue), they'll release a large puff of their element when they die, which can affect the player.
"Powerful foes" with weak-point gauges will generally have moves corresponding to the four combat runes, which the game prompts the player to use in defeating them. They can be defeated without use of the specified runes, but it is more difficult. A single powerful foe may or may not have moves corresponding to all four combat runes.
Chuchus with weak-point gauges do not spawn until the very late postgame or possibly the DLC. However, they do exist in the game.