It is not clear if it is intended to and does work with other Hero Powers that draw cards or not; for example, Wilfred Fizzlebang has been seen to work with the Medivh's Hero Power Brilliance in One Night in Karazhan but not with the Tavern Brawl Hero Power Harvest or the Dalaran Heist Shaman Hero Power Refresh .
The mana cost of cards drawn by eligible Hero Powers is set to 0 through a cost-modification enchantment attached to the card.
Example: If Wilfred Fizzlebang is killed or silenced the cost-modification enchantments created through his effect are not removed.
Example: Copies generated by Chromaggus will not benefit from Wilfred Fizzlebang's cost reduction, since copy effects do not copy cost-modification enchantments.
This card's effect follows the general rule that multiple cost modifications take effect in order of play; for additional details, see Mana cost.
"You! Yes, you! Gaze upon me and treasure this moment of meeting, for soon the world will come to know and fear the name and stern visage of Wilfred Fizzlebang! Once my magnificent summoning is complete, no one will doubt my ability!"
Wilfred Fizzlebang yells: Thank you, Highlord. Now, challengers, I will begin the ritual of summoning. When I am done a fearsome doomguard will appear!
Wilfred Fizzlebang yells: Prepare for oblivion!
Wilfred Fizzlebang yells: A-HA! I've done it! Behold the absolute power of Wilfred Fizzlebang, master summoner! You are bound to me, demon!
Lord Jaraxxus yells: TRIFLING GNOME! YOUR ARROGANCE WILL BE YOUR UNDOING!
Wilfred Fizzlebang yells: But I'm in charge here...
Lord Jaraxxus kills Wilfred Fizzlebang.
Lord Jaraxxus yells: INSIGNIFICANT GNAT!
Before Patch 188.8.131.5257 (Mech War Tavern Brawl patch), if you played a card reduced to 0 mana cost by Wilfred Fizzlebang and targeted it with Recombobulator, it would recombobulate into a 0-mana minion. This bug has been fixed, and the base mana cost is now used again.