Summary: Thanks to the luke75 for catching this. Apparently unlike cubics, each mimic’s sacrifice abilities are different.  I have assumed that they are the same and completely ignored them until now.  But this clearly shows they are different.

Race – Egg
Affiliation – None

2/1/2/0

– When you successfully cast a spell and the spell is placed on your graveyard, you may sacrifice Blue Mimic for a non-Ultrarare Water creature from your hand. This summoned creature cannot attack this turn. This does not end your turn

(A) None (C) None (B) S 

Comment: Remember that the Red Mimic sacrifice was based on the reactivation?  This one seems much more interesting mechanism to trigger the sacrifice ability.