Can only be special summoned when you control no monsters and your opponent controls a monster.
You can Special Summon Unknown Synchron from your hand and use Machine Duplication to summon 2 more Unknown Synchrons from your deck. You can then use those monsters as tribute for something big like an Egyptian God or Destiny HERO - Plasma.
Genex Neutron is able to search out Machine-type Tuners during the End Phase of the turn he was Normal Summoned. You can then use both Unknown Synchron and Genex Neutron the next turn to make a level-5 monster.
Unknown Synchron Special Summoning condition requires that there be a monster on your opponent’s field. Use Synchro Material to use that monster with Unknown Synchron to make your Synchro monster.
Special Summons itself from your hand
This card needs more love.
Darklords can tech it to pull out a super easy Star Eater! That's totally meta, but people seem to forget this card exists altogether.