Using

tmp = ContourPlot[{y^4 + 6 x^3*y + x^8 == 0, y - x^3 == 0}, {x, -5, 5}, {y, -5, 5}]

How can I get the pair values used to plot these two curves?

For example: x^2 + y^2 - 1 = 0 , (2,Sqrt(-3)) is a point of the curve.

Thank you.