Wow!
This is a great card. An elegantly simple mechanic results in complex play with complex tactical and strategic consequences.
+98 rep
There is probably enough of a difference between below and above that the cost decrease is unneeded. I would go with same cost as the card chosen. But a fixed
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cost might be necessary. (Ask Xenocidus about the coding)
If it chooses earlier drawn cards then it initially has a list of options but the options are limited.
If it chooses later drawn cards then initially it has no options but its options continue to grow with a much higher bound.
So is choosing earlier or later drawn cards better? I think choosing later drawn cards is better and thus would be the upgraded version.