MTG >Combos >Phyrexian Walker +Ornithopter +Urza, Lord High Artificer +Hullbreaker Horror +

1)

Urza, lord high artificer

,

hullbreaker horror

, and

phyrexian walker

must be must be on the battlefield 2) Tap

phyrexian walker

to add 1 blue mana to your mana pool, using

Urza, lord high artificer

's ability. 3) cast

ornithopter

and return

phyrexian walker

to your hand using

hullbreaker horror

's ability. 4) Tap

ornithopter

to add 1 blue mana to your mana pool using

Urza, lord high artificer

's ability. 5) cast

phyrexian walker

and return

ornithopter

to your hand using

hullbreaker horror

's ability. 6)repeat the process. Note: any 0 cost artifacts can be used for this combo