break it down like this:

-----------
Killer butter bee:
- homozygous for pastel trait
-heterozygous for spider trait
- heterozygous for butter trait
------------

Both parents have to carry the pastel trait to create an animal that is homozygous for the pastel trait.

For each of the heterozygous traits (spider and butter), only one parent has to carry.

So possible breedings:

butter spider pastel x pastel
butter pastel x spider pastel