Smite

[Birdbrain]

What happens to the blocking creature when {smite} is played? It takes damage? No damage?

[Mentonin]

If cast before the damage step, it wouldn't take damage, as thought it hadn't been assigned as a blocker

[Gorzo]

Assuming you cast {Smite} after declaring blockers but before damage, the blocked creature won't be alive anymore to deal damage. Your blocker will be undamaged and peachy-keen.