avatar of woe Phantasmal Image 10 cards in graveyard copy cost?

[Kabutops]

if i have more then 10 cards in my graveyard

i cast Phantasmal Image as copy of avatar of woe

does it cost me free or U?

[Arix]

Neither. It costs you the full 1U. Phantasmal Image doesn't become a copy of the Avatar until it enters the battlefield, which happens long after you've already paid the cost.

[Kabutops]

does that mean if i copy a Acidic Slime i wont get to destroy artifact, enchantment, or land?

[Arix]

Yes, you will.

[Kabutops]

but u said it only becomes copy after enters the battlefield so isnt that too late?

[Arix]

No. It enters the battlefield as a copy of the creature, so any abilities that the creature has that triggers upon it entering the battlefield will trigger.