Spawning Bed

{T}: Add {C}.
{6}, {T}, Sacrifice Spawning Bed: Create three 1/1 colorless Eldrazi Scion creature tokens. They have "Sacrifice this creature: Add {C}."

Pioneer Masters

Young Eldrazi crawl forth from the dust, compelled by a greater will.

Modern Horizons 3 Commander

Battle for Zendikar

{T}: Add {1} to your mana pool.{6}, {T}, Sacrifice Spawning Bed: Put three 1/1 colorless Eldrazi Scion creature tokens onto the battlefield. They have "Sacrifice this creature: Add {1} to your mana pool."

Eldrazi Scions are similar to Eldrazi Spawn, seen in the Zendikar block. Note that Eldrazi Scions are 1/1, not 0/1.

Eldrazi and Scion are each separate creature types. Anything that affects Eldrazi will affect these tokens, for example.

Sacrificing an Eldrazi Scion creature token to add {C} is a mana ability. It doesn't use the stack and can't be responded to.

Some instants and sorceries that create Eldrazi Scions require targets. If all targets for such a spell have become illegal by the time that spell tries to resolve, the spell won't resolve and none of its effects will happen. You won't get any Eldrazi Scions.