Some creatures are magical by nature, others use magical spells, yet others wield magical weapon to defeat their foes.
All attacks made by spells and magic items are considered to be magical attacks, as are all attacks that are specifically noted as being magical attacks. Shots fired from magical items are also considered to be magical attacks, unless their description specifically states otherwise. Hits inflicted by rolls on the Miscast table are treated as magical attacks. Note that spells are never considered to be physical attacks.