I'm not sure comparing this to Mummy is such a good idea. I think Mummy is pretty much a way for newbies to access Pharaoh, even though it requires a duo and two cards to do so (or a trio to use devour), although it does work well in a death rush. In addition to that, it seems to me that mass-quint, even if temporary (which I assume it is) should warrant more than a +1 cost compared to Mummy. If anything, it reminds me of Cloak, with the condition that only Time-element creatures can be affected (although unupped affects both sides, like Pandemonium) Cloak is 4
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-> 3
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for two-turn mass-PA/quint that can be disabled by any form of mass-CC or PC, while Pandemonium is 3
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-> 5
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for limiting a mass effect to the desired side of the field. Sphinx can be removed by most forms of CC (presumably including lobotomization), but only affect Time-element creatures, and so is both weaker than Cloak (due to lesser coverage) and stronger than the same (due to lower variety of counters- PC can get rid of Cloak but not Sphinx) Therefore, I would value the mass-protection at +2, and the limiting of said effect to the desirable side of the field at +3 (judging from pandemonium, accounting for -1 value from upgrading), and so would give the unupped a quanta cost of 5
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(from attack) + 2
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(from protection) for 7
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, or 6
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if you want it to be similar to Mummy, and the upped a cost of 5
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(5 attack) +2
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(from protection) +3
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(from desirable limiting) -2 (from upgrading) for a cost of 8
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(or 7
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, for comparison to Mummy)