The standard species of Sidehopper are found throughout the mild temperature regions of Brinstar. As their name suggests, they use their strong legs to athletically leap around their environment and attack intruders.
Small Sidehoppers are quickly killed with a Missile, but beam weapons, or a single Charge Spin Attack will work well too.
Large Sidehoppers are much more resistant to attacks, and while it’s safest to kill them from a distance with multiple missiles, this can drain a lot of ammo. Unless more powerful beam weaponry has been acquired, use a Power Bomb to take out any nearby.
Given their large weight, it’s unknown how Sidehoppers (as well as Desgeegas) can perform this, but they are capable of jumping upside down across the ceiling.