Should actually be blizzlike. Those abilities are called "Magic Damage Melee Special Attacks", for details see
http://www.wowwiki.com/Attack_table" Magic-damage melee special attacks
Some monsters also have melee "specials" (the equivalent of yellow-damage attacks done by players) that do magic damage. For example, the Crystal Strike ability of the Erratic Sentries on the Isle of Quel'Danas inflicts Arcane damage, but is resolved as an ordinary melee special attack—it can miss, be dodged, be parried, and be blocked, and does double damage on a crit. The only difference between how a magic-damage melee special attack, and an ordinary physical damage melee special attack, is resolved is that if the target has any resistance to that school of magic, the same check is made to see if the damage is partially resisted as would happen from a spell. "
So instead of being mitigated by Armor Value, they are mitigated by the target's resistance. Whole attack table still applies since it's a melee ability.