Mathas, Hunted Fiend

Mathas, Hunted Fiend, costs {1} less to cast, and
gets +1/+1, for each aura curse you control.
Aura curses you cast have cascade, but can
only cascade into other curses.
At the beginning of each player's upkeep, that
player untaps and gains control of Mathas,
Hunted Fiend, then Mathas, Hunted Fiend
gains haste and flying until end of turn.