excrescence         
noun [ C ] uk/ekˈskres.əns/ us/ekˈskres.əns/
 formal赘生物;赘疣;瘤 
an unusual growth on an animal or one of its organs or on a plant
  literary丑陋不堪之物;大煞风景之物 
something considered to be very ugly
  The new office development is an excrescence on the face of the city. 新近开发的写字楼破坏了市容市貌。