Chu Chus are gel-like droplets that hop to get around. They can be killed with any weapon, but it is best to attack from a ways away.
Majora's Mask is the first game that Chu Chus have appeared in. They drop different things depending on their color. Yellow Chu Chus drop arrows, red drop hearts, and green drop magic.
There are 5 different kinds of Chu Chus. Red Chu Chus have no significant traits and sometimes drop Red Chu Jelly. Green Chu Chus will sometimes collapse so that you can't hit it with your sword. They occasionally drop Green Chu Jelly. Yellow and Blue Chu Chus are identical, aside from color, and sometimes drop red or green Chu Jelly. Purple Chu Chus collapse every time you attempt to strike them, making swords futile against them.
The first boss in this game is a Big Green Chu Chu, and the mini-boss of the Temple of Droplets is a Big Blue Chu Chu. Two new types of Chu Chus appear in this game. The rock Chu Chu has a rock on it's head that can only be destroyed by a bomb, turning it into a red Chu Chu. The Spiny Chu Chu also appears in this game, and it's head occasionally turns into a ball of spikes, making it temporarily invincible and painful on contact.
There is nothing significantly different about Chu Chus in Phantom Hourglass compared to the other games.
Two more new Chu Chu types appear in Spirit Tracks, the Spiny Chu Chu and Ice Chu Chu. Spiny Chu Chus are Red Chu Chus wearing a helmet covered in spikes that can be pulled off with the Whip, rendering it a Red Chu Chu. Ice Chu Chus are kind of self explanatory; they live in the Snow Realm and freeze you on contact.
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