Oil

אָמַר רַבִּי לֵוִי לָמָּה חָלַק קֹרַח עַל משֶׁה, אָמַר אֲנִי בְּנוֹ שֶׁל שֶׁמֶן בֶּן יִצְהָר, שֶׁנֶּאֱמַר (דברים ז, יג): וְתִירשְׁךָ וְיִצְהָרֶךָ שְׁגַר אֲלָפֶיךָ וְעַשְׁתְּרֹת צֹאנֶךָ עַל הָאֲדָמָה אֲשֶׁר נִשְׁבַּע לַאֲבֹתֶיךָ לָתֶת לָךְ. תִּירוֹשׁ, זֶה יַיִן. וְיִצְהָרֶךָ, זֶה הַשֶּׁמֶן. וּבְכָל מַשְׁקִים שֶׁתִּתֵּן אֶת הַשֶּׁמֶן הוּא נִמְצָא עֶלְיוֹן,

How does a play on his ancestor's name convince Korach that he is right?  Korach was of the opinion that a leader must be like oil, rise above everyone else.  However, oil has another aspect to it and that it is that it permeates through everything it comes in contact with.  Korach felt he was suited to be the leader for he understood that he was able to be elevated and exalted above everyone else.  However, what he didn't eternalize is that a leader is not meant to detached from everyone else but has to be able to make an impression on everyone.  The leader has to be able to touch everyone and inspire them to be better people.  That was Moshe and Aharon.