There is no hippowdon in heart gold and soul silver
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Some Pokemon have different sprites due to their gender e.g. a female Pikachu has a heart tail whilst a male one has a straight edged one, this black Hippowdon is like this as it is female, the yellow Hippowdon you are referring to is a male.
Hippopatas is what evolves into hippowdon.
you can find hippowdon on route 228
Hippowdon is a Ground type pokemon.
He is benevolent with a heart of gold. - She is beautiful and she has a heart of gold.
the gaurdian of the hippowdon temple is cresselia.
You catch Hippowdon at Route 228 where the sand is and you catch hipportas at route 224 in the ruin maniac cave which evolves to Hippowdon at lv34
A heart of gold itself is an expression relating to someone kind. "They have a heart of gold".
Hippowdon is #450 in the national pokedex, and it is a Ground type Pokemon.
It's Darkrai. You can't get him in Heart Gold.
Elite four Bertha has a Hippowdon. Just battle her and she'll send out a Hippowdon.
Hippowdon is a Ground-type Pokémon and is weak against Water, Grass and Ice.