Forum:Syncro summoning

The other day I was playing an alien deck, and my opponent had out Code A Ancient Ruins, an equip card, and and then played Alien Ammonite, and then brought out a level four alien. He then proceed to do an a combo with Code A Ancient Ruins, by bringing out 3 Cosmic Fortress Gol'gars and Ally Justice Castor. He says that by syncro summoning, he is destroying his aliens, allowing him to get the A Counters for Code A Ancient Ruins. Does syncro summoning "destroy" the monsters being used for syncro summon?