Original Card

I needed a 2 cost solid playable creature that messed with blocking and happened to be a Dwarf. I ended up with this. Personally, I think the ability is neat. My only regret is that it doesn't do anything in multiples. Ah well. I suppose if the Dwarf deck was too evasive, there wouldn't be much use for Dwarven Pony.

I'm reading this as a terrible way to say all creatures can't block, which I doubt is what you mean. I think a much cleaner way to accomplish basically the same thing is "When ~ attacks, defending player chooses a creature they control. That creature can't block this turn." It even stacks that way! I'd prefer "... target creature can't block," which is pretty common in red and prevents the opponent from just choosing tapped creatures or whatever to not block.

Your first suggestion makes more sense than the way this is currently written, Dude. I'm editing to say that. Though, your first version doesn't stack like you think it does. The opponent just keeps choosing the same creature. Honestly, though, I'm cool with that. I just like the idea of a creature that says "Not everything can block".

An alternative alternative. This card could say "...the defender chooses target untapped creature they control..." I'm not sure if adding targeting restrictions adds value here? Or does that just make it that much more confusing for common?