Flame Burst

Ok, so I used flame burst in the corner on Gray Town Rats, however, it didn't hit it so I wasted crystals.

Maybe they were just out of range?

Or it could be just one of those displacement glitches. You or the rats were at that spot on your screen, but offset slightly on the server, so Flame Burst activated but didn't touch them...

...Or they could have just moved away.

these things happen often with flame burst

I'm guessing it's the displacement, because the rats were in place when i shot and during the flame burst animation.