The Story of Chibi Chibi:

Chibi Chibi can't really talk because she's only 2. The first words she can say are "Chibi Chibi" and repeat anything anbody can say. She and Eternal Sailor Moon created a new tial for Eternal Sailor Moon to use in battle. In episode 187 or something Chibi Chibi turns into Sailor Chibi Chibi Moon. Eternal Sailor Moon cries, "Chibi Chibi Moon!?"

Sailor Chibi Chibi's Powers

I haven't actually seen any of these powers yet because I live in Canada, so I'll just give an answer except I'll rephrase it in my own words.

*SMSSS Powers*

*Chibi Chibi Crystal Power!*
Chibi Chibi says this to transform into Sailor Chibi Chibi Moon.

Note: She did give Eternal Sailor Moon a new attack! Silver Moon Crystal Power Kiss! Used to transform enemies back into there old self again.

Let's see some of Chibi Chibi's appearances:

Sailor Chibi Chibi Moon
Chibi Chibi