How about:

1) Someone dressed as the Easter Bunny or the 
Japanese equivalent.

2) A cel featuring eggs, jelly beans, or baskets 
full of candy (Easter or any Japanese equivalent)

3) Or for those of religious disposition, a cel 
of some anime character being crucified or rising 
from the dead (ideally in a nice vs. nasty way).

I'll start with the last of these, one of CLAMP's 
creepy uses of the Crucifixion image.