Halloween: Kids dress up in costumes.
Purim: Kids dress up in costumes.
Halloween: Kids go door to door, asking for treats and threatening with "tricks" in case they are turned away, teaching greed.
Purim: Kids are asked to deliver mishloach manot, food portions to friends, and also to give mishloach manot to their friends. One other mitzvah of Purim is giving to the poor, so yeah, this holiday teaches just the opposite of Halloween.
(That said, I have nothing against Halloween. Luckily it is not part of my country's culture, and while it is being pushed on a lot of different cultures, I much much prefer the native holidays.)