From experience, I've had less replies on any posts I've started with
PEACH. Try removing that from the title and seeing if you get more apt replies.
That aside, The item looks okay, but a little convoluted. Let me try my hand at cleaning it up and tell me if it still does what you want it to.
Onyx Skull
This dangerous looking skull can be attached to an implement and improve necromantic powers.
Lvl 1___+1___360 gp___Lvl 16___+4___45,000 gp Lvl 6___+2___1,800 gp___Lvl 21___+5___225,000 gp Lvl 11___+3___9,000 gp___Lvl 26___+6___1,125,000 gp Item Slot: Implement (augment) Property:When this augment is not bound to an implement, roll 1d20 at the beginning of each encounter. On a natural 1, you summon an uncontrolled skeletal minion in an adjacent square which is considered an enemy by you and your allies. The minion lasts until destroyed. You gain no other benefit of this augment unless it is bound to an implement. Binding to an Implement: During a short rest, you can bind or unbind (but not both) this augment to an implement in your possession. You can only bind it to an implement of its own level or higher. The enhancement bonus of the bound implement becomes this item's enhancement bonus instead. You also gain the following property and power. ___Property: When bound, you add your implement enhancement bonus to the attacks and damage of any skeletal minion you summon. If your skeletal minion scores a critical hit, it deals 1d8 extra damage per plus of the implement.
___Power (Encounter * Necromancy, Summoning):No action. At the beginning of each encounter, roll a d20. When you roll a natural 19 or 20, you summon a skeletal minion under your control in an unoccupied square adjacent to you. This minion lasts until the end of your next turn. On a natural 1, you instead summon an uncontrolled skeletal minion in the same square, which counts as an enemy to you and you allies and lasts until destroyed.
___Level 6 and Higher: If you are a necromancer of 5th level or higher, a natural 1 does not summon an uncrontrolled skeletal minion.
Usually at-will attacks only keep something around until the end of your next turn at best, so that's why I included it. This also handles the issue of attaching it to something and clears up when you can use certain powers/properties. Finally, keeping the skull's enhancement bonus instead of the implement's provides reason to upgrade the skull later instead of buying it once and forgetting about it.
I hope it helps
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