Nice blocker :)
Untap, upkeep - pay the 1U, Mt, Dauthi Cutthroat, Done.
Spidey 18
Hand: 11
In Play:
(T) Plains
(T,U) Island x2
(T) Swamp
(T) Mt
(U) Shield Mate (1/1, sac ~: target creature gets +0/+4 ueot)
(U) School of Piranha (3/3, at the beginning of my upkeep, sac ~ unless I pay 1U)
(U)...