My cat gets spooked when i wake up?

[goddessgalaxia]

Some times my cat will get spooked and do this howl/growl/meow combo thing when I wake up from sleep. Most of the time it happens if someone calls on the phone and I get up real fast to try and answer the phone. I dunno if he does this because the ring scared him. Or if me jumping up fast scares him, but he will attack if i get close to him at that point. He does not do it often. I don't quite understand why he does this. Considering he doesn't do it always even when the phone rings.. what could be the reason of him being like this? After about 15 min he is back to him self and lovey...