Hi the tube looks like a worm, the white blob could be a pineapple sponge, both of wich are harmless.
How olds your tank?
Frog spawn can be very sensitive, if they don't like were they are the heads will bail out of the skeleton and settle somewhere else and make a new one. In a reef tank the head just dies.
To much flow or water conditions will make them bail out.
The acan could be a crab, did you use live rock?