Odric, Oppressive Rays
AgentSmith can choose to have Neo's creature block, and if somehow Neo already has the {3} necessary to pay for Oppressive Rays in his mana pool (thanks to Kruphix, God of Horizons, for example), his creature will block the way AgentSmith wishes and Neo will have to pay for the privilege.
But if Neo doesn't have the necessary mana already in his mana pool, he doesn't have to produce any if he doesn't wish to. If he chooses not to produce the mana, this will result in the declaration of blockers becoming illegal, and it will be reversed. Unless AgentSmith can somehow convince Neo to cooperate and produce the mana that would allow his creature to block the way Smith wishes it to (which is unlikely), Smith will have to abandon his attempts and stop trying to have the creature block.
Nothing changes if the enchanted creature is Spirespine; creatures with unpaid costs to attack or block are exempt from requirements that they do so.
Daniel Kitachewsky
L4, Paris, France
Rules NetRep