World Erupter

Trample, reach, vigilance, nonbasic landwalk
Other Wurm and Hydra creatures you control get +1/+1 and have indestructible.
If World Erupter would be exiled, instead you
may sacrifice it and each Wurm and/or Hydra creature you control deals damage to target creature or player equal to its power.
Deep down is where ancient powers dwell.