A little bit of Fridge Brilliance here but Bunsen being friends with Cosmo makes sense since both are mythical creatures thought to be non-existent and they were created by Butch Hartman.
Amanda states in the theme song that she doesn't want Bunsen's kind to be increased, which raises the disturbing question on if she'd try to sterilize Bunsen (or even wipe out the females of his species) to prevent him from procreating.
