Neat solutions provided, but there are probably more straight forward ways to solve the original problem. One of these might help. 
 
In:= s=0; Apply[Do[s+=i^i,{i,##}]&,Hold[1,12,3]]; s 
 
Out[75]= 10000823800 
 
 
In:= r=Hold[s=0;{1,12,3};s]; 
Part[r,1,2,0]=(Do[s+=i^i,{i,##}]&); ReleaseHold[r] 

Out= 10000823800