About Scales for HP, here are my methods: http://www.gamespot.com/ds/puzzle/scribblenauts/show_msgs.php?topic_id=m-1-51888745&page=1#m-1-571927992
Throws of junk do -2, -3, or -5 HP; I forget which do which, also which do -1 HP. Top weapons do -250 HP, then -125, -100, -50, and on. Lava and red magic do -500 and bombs and shells do -1000 (I guess). My notes so far—there are very few rungs:
1000 HP God/Zeus, Algolagnist/Angel_of_Death//Hades/Death/Morrigan/Mors/Reaper/Grim_Reaper/Thanatos/Yama/Yamaraj, Cthulhu/Cthulu, Hydra, robosaur, savior/Scott/superhero, and djinn/genie/jinn/sword_swallower
900 dragon
725? Meka
600 acrocanthosaurus/albertosaurus/alectrosaurus/t-rex/trex/tyrannosaurus/tyrannotitan
500 mammoth and clone/doppelganger/Maxwell/me/mimic/myself/player/scribblenaut/shadow/shape_shifter; tank, reconnaissance_aircraft/bomber_(stealth)/stealth_bomber/flying_wing, flying_saucer/UFO/USO, and adhesive/rubber_cement/glue/paste/spackling_paste/pitch/poster_putty/resin/spackle
400 Nessie/Champ, Scylla, Bigfoot, Yeti, bear, ape, pterodactyl, kangaroo/roo, and hippopotamus; car and gyroglider
350 ettin/giant/ogre/titan, sand_worm/death_worm/Lambton worm, and whale
300 cow, horse/mare, Trojan_horse/warhorse/rouncey/rouncy/rounsey/sleipnir/stallion, shark, and dolphin; car's tire/tyre
250 Adam/adult/agenhina/buddy/client/dad/father/friend/guy/human/male/man/big_man_on_campus/teammate/neighbor/pa/pal/papa/parents/pedestrian/person_(man), Eve/female/gal/homemaker/sign_language_interpreter/ma/milkmaid/mom/mother/parent/person_(woman)/resident/spinster/woman/wife/housewife, babe/chick, husband, demon/devil/Fiend/imp/incubus/Satan, succubus, siren, Hercules/warrior, dryad/nymph, anaconda, Ginny_Greenteeth/Jenny_Greenteeth/Peg_Onell/Peg_O_Nell/Peg_Prowler/Wicked_Jenny, frost_giant/ymir, croc/crocodile, Feep/robot_zombie, phoenix/susaku, living_dead/undead/zombie, boggart/bogey/boogy_man/boogey_man/kobold/lizard_man, and Edison/Edy; Starite, one-fifth of optical_cable/SATA_cable/USB_cable/conduit/USB_cord/zip_line/USB/wire/piano_wire/zip_wire, one-fifth of extension_cable/extension_cord/shock_cord/extension_lead/power_lines/telephone_lines, and one-fifth of cable
200 crab, lobster, and clam
175 baimaiden/girl/flower_girl/niece/teen/pre_teen/tween and boy/page_boy/school_boy/schoolboy/child/children/young_guy/kid/young_man/nephew/orphan/rascal/ringbearer/teenager/toddler/urchin
150 dog, cat, colt/foal, calf, lemur, monkey, hedgehog, hog, bass, leveret, and joey
125 ; board/plank/prop/wood, one-fifth of chain_(tool), one-sixth of rope/tightrope/highwire, and one-third of aglet/cord/shoelace/shoestring/tourniquet
100 Maxwell, baby/minor/newborn/RNA/zygote, bird, duck, chick, snake, frog, fish, turtle, and octopus; tire/tyre, box/wine_box/crate/shipment, and one-third of floss/clothes_line/streamer
90 tadpole
75 legless_lizard, lizard, and catfish
50 bat, mouse, squirrel, and scorpion; one-third of hand_cuff/hand_cuffs/handcuffs/shackles, one-fifth of hose/garden_hose, and one-fifth of fire_hose
45 abalone/muttonshell/ormer/perlemoen
40 jellyfish
25 fly/gnat, bee, mite, tick, leech, cricket, and spider
15 worm and larvae