Was scuba diving out on a shore dive site on Alki. A place we called "WeatherWatch Park(er).
http://staff.washington.edu/parker/scuba/reviews/weatherwatch.html for those that are interested in the dive.
It's a huge eel-grass flats. At the end of the flats is the start of a nice slope that goes down well beyond 200'. After doing the dive, one follows a compass heading underwater and swims in the 10' eel grass shallows to shore. As my buddy and I were plodding along in the shallows, we were starteled as all hell when a massive bull sea lion put itself between us and the beach and would not let us pass! It would come right up to our face and bark and blow bubbles. As we all know, blowing bubbles is a sign of aggitation and aggression for sea lions. Didn't help much that we were on open-circuit scuba..hence all kinds of bubbles every time we breathed. (Where's the rebreathers when you need them???)
After about a 10 minute stand off, the sea lion finally went away and we were able to make it to shore. Scared the living snot out of us. You don't realize how slow and vulnerable you really are underwater until some massive animal dances around you like you were frozen. It could have easily killed us if it wanted to. Not a damn thing we could have done about it.
Needless to say, I have a great respect for all underwater critters - especially big and fast ones with really large/sharp teeth.