Michele's (who was 13) bare buttocks can be seen several times throughout the movie, often for prolonged periods.

13-year-old Michele is seen naked on several occasions, however, camera angles and other objects in the world cover his genitals.

Michele uses his invisibility power to spy on several girls his age in the shower at school. We do not see this, but we do see the girls in their underwear afterwards, with the naked Michele spying on them. While in there with them, Michele's invisibility wears off, and the girls catch him watching them.

While Michele is invisible and naked, he kisses Stella under a towel. We see an obscured shot of this.

Stella's (13) underwear is seen in several upskirt shots when she wears her gymnastics costume. Also her nipples are nearly visable through her gymnastics costune as well as in a later scene in the movie.