Wow, good play. I'll pay 2 and sac a Forest, Mt, and Island
Spidey: 18
Hand: 10
Battlefield:
(T) Forest
(T) Island
(U) Elvish Berserker (1/1; Whenever ~ becomes blocked, it gets +1/+1 for each creature blocking it)
(U) Cinder Crawler (1/2; R: ~ gets +1/+0 ueot. Activate this ability only if ~ is blocked)
(U) Pygmy Troll (1/1; For each creature that blocks it, ~ gets +1/+1 until end of turn.; G: Regenerate ~)
(T) Thalakos Scout (2/1; Shadow; Discard a card: Return ~ to its owner's hand)
(S) Whiptongue Frog (1/3; U: ~ gains flying ueot)
Graveyard: Forest, Mt, Island
Exile:
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Mooseman: 16
Hand: 11
Battlefield:
(T) Plains
(TT) Island
(T) Mt
(TT) Forest x2
(R) Onslaught (Whenever you successfully cast a creature spell, tap target creature.)
(U) Welkin Hawk (1/1, Flying If Welkin Hawk is put into any graveyard from play, you may search your library for a Welkin Hawk card, reveal that card to all players, and put it into your hand. Shuffle your library afterwards.)
(U) Pygmy Troll (1/1,For each creature that blocks it, Pygmy Troll gets +1/+1 until end of turn. G: Regenerate Pygmy Troll.)
(U) Avenging Druid (1/3, If Avenging Druid damages any opponent, you may reveal cards from your library until you reveal a land card. Put that land into play and put all other revealed cards into your graveyard)
Graveyard: Fade Away
Exile: