あまつちゃん（かっしーちゃんなのに菓子じゃない！）
次回人を笑うものは人に笑われる

Amatsu-chan: (She's Kasshii-chan, yet she's not giving kashi!) Japanese for "candy". Sadly, the cereal Kashi would maintain the pun but wouldn't fit the context.
Next: One who laughs at someone is laughed at by someone too.