To dream of a killer whale represents overoptimism. Situations where you overestimated how wonderful or positive something is. Killer whales may also reflect fear for things that you initially viewed as positive. A killer whale may be a sign that you that you are in denial or overconfident. Thinking something is good idea and then scaring yourself as soon as it begins to happen for real.
Killer whales may also reflect your feelings about how wonderful it will be to meet or talk to someone you really like and then being terrified when you get the opportunity to spend time with them for real.
Example: A woman once dreamed of standing in front a killer whale. In real life she was close to getting married. The killer whale reflected how wonderful the idea of getting married and the fear she felt when it time to actually do it.
Example 2: A young man dreamed of seeing a killer whale. In waking life he was considering telling a girl how he really felt. The killer whale represented how good it felt to think about telling her his true feelings and the terror he felt when he was about do it for real.
Example 3: A woman dreamed that killer whales might bite her legs. In waking life she was fearing her faith in God being tested when a situation got too difficult. The killer whales in this case may have reflected her feelings about wonderful believing in God was, but also how scary it felt to think God didn’t matter when she was in trouble.