Eva-A Pendulum Monster placed in the Pendulum Zone is not treated as a monster, by rather as a Spell Card, and also as a card in the Spell & Trap Zone.
EX: A card in the Pendulum Zone is still treated as a card in the Spell & Trap Zone, so "D/D/D Dragonbane King Beowulf's" effect of "Destroy all cards in the Spell & Trap Zones" can destroy them.