You do have to choose a source when you activate it
Since the choice is obvious who cares....
Boom Boom out go the lands
Play MT
Pump the ogre
attack with ogre and Dryads for 5, with one prevented
done
Spidey: 11
Hand: 5
In Play:
(U) Mt
(T,T) Island x2
(T) Forest
(T) Plains
Lifetap (Whenever a Forest Mooseman controls becomes tapped, I gain a life)
CoP: Green (1: The next time a green source would deal dmg to me this turn, prevent that dmg)
(T) Mox Jet (T: Add B to my mana pool)
(U) Mon's Goblin Raider (1/1)
(T) Hill Giant (3/3) ~Paralyzed~!LUSTY!
(U) Merfolk of the Pearl Trident (1/1)
(T) War Mammoth (3/3, Trample)
(U) Nettling Imp (1/1, T: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That creature attacks this turn if able. If it doesn't, destroy it aeot. Play this ability only during Mooseman's turn, before attackers are declared)
(S) Plague Rats (1/1, ~'s power and toughness are each equal to the # of creatures named ~ in play)
Graveyard: Dark Ritual, MT, Island, Island, Forest, Plains
RFG:
Mooseman: 14
Hand: 9
In Play:
(T) Mountain
Paralyze ("When Paralyze comes into play, tap enchanted creature.
Enchanted creature does not untap during its controller's untap phase. That player may pay an additional 4 during his or her upkeep to untap it.")
Firebreathing (R: Enchanted creature gets +1/+0 until end of turn.)
Wanderlust (During the upkeep of enchanted creature's controller, Wanderlust deals 1 damage to him or her.)
Circle of Protection: White (1: Prevent all damage to you from a white source.)
(T) Llanowar Elves (1/1, T: Add G)
(T) Gray Ogre (2/2) *Firebreathing*
(T) Dwarven Warriors (1/1, tap: Target creature with power 2 or less is unblockable this turn.)
(T) Shanodin Dryads (1/1 Forestwalk)
Graveyard:Forest, Mountain, Swamp, Plains, Armageddon
RFG: