They just look funny as it almost seems that the giants "dance" so sayomie placed some at spawn for the lols. We cant get them to spawn yet... If anybody has an idea about what spawn rules giants have pm me <object class="emojione" data="https://resources.enjin.com/1489581540/themes/core/images/emojione/svg/1f642.svg?0" type="image/svg+xml" standby=":)">:)</object>
From the MonsterBox website: It will not spawn certain types of monsters (like Giants or Steves) because the spawn rate and spawn conditions for a monster spawner of that type is not defined in the minecraft code.