This allows you to challenge them if they hadn't been exerted already
When it comes into play, it taps down all legendary creatures, and it keeps legends from 'readying' in the untap phase, potentially locking them down for the rest of the match
Turn one, draw a card, play nothing, discard a card in the cleanup step, throw Primeval Spawn into the graveyard, turn two basic swamp, cast Reanimate targeting Primeval Spawn is totally something you I would try do in a game of EDH if the restriction wasnt present
Attacking and making land drops are two of the most fundamental parts of Magic , and being rewarded for simply playing the game is extremely potent
Martyrs Bond offers a little more protection by spreading the pain around, though admittedly at a higher cost
That leaves us with 3 good learn cards and another 3 or so that are potentially enough for cube