Thag's Ascension

You may cast this spell as though it has flash if
any opponent controls creatures with total
power 10 or more.
Exile any number of creatures you control, then
return those creatures to the battlefield with an Indestructible counter on them.
"Millennia ago, our ancestors could only dream of
living safely on Alenda Bel Thag. Thanks to the
Ascension, we can thrive here."
—Gigaphos, the Teacher