Ugh, I guess I'll Undermine it.
Untap, upkeep, Draw
Watery Grave (not paying), Nettling Imp, activate the Mask
Done.
Spiderman: 20
Hand: 3
Library: 39
In Play:
(U, U) Underground Sea (B/U Dual) x3
(T, U) Watery Grave (Ravnica B/U Land) x2
(T, T, T) Underground River (B/U Pain Land) x3
(T)...