Giant Vermin Spell
D&D Giant Vermin Spell Description: You turn three normal-sized centipedes, two normal-sized spiders, or a single normal-sized scorpion into larger forms. Only one type of vermin can be transmuted (so a single casting cannot affect both a centipede and a spider), and all must be grown to the same size. The size to which the vermin can be grown depends on your level; see the table below.
More: D&D Spells for Giant Vermin