Though it may be altering the card far to much, I would personally change the card such that it is of either the
or
element and have its effect be:
InvisibilityConceal all friendly creatures, all friendly creatures then randomly swap places with each other. When a new creature is played, Invisibility is activated again, but its countdown is unaffected.
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*Conceal would be a passive ability. When a card is concealed, it is targetable but cannot be seen by the enemy. After being targeted, it is revealed and affected by whatever is targeting the card unless it is revealed and is untargetable.
It should allow targetable creatures to be targeted, but their identities left unknown, making a Reverse Time, a Thunderbolt, or a Congeal possibly ill-chosen. This would mean serious reworking of AIs.
Perhaps however damage order may give away position. Is damage inflicted in order of play timeline or by field position? If it is by field position, then this idea is kind of flimsy, more so when played against the pros.