Experiment No.2 is found in the manhole near the Witch's house during and after the Grim Tales quest. This monster does not have any relation to the Summoning skill. This monster has both a melee and ranged attack, although it will only use one style depending on your distance from it.
Note: The monster's defence against a particular style of combat increases quickly as you attack it with that style. It does not carry over from one monster to the next.
Looking at the creature from side on you can see that it has the child's ball stuck to its head, from the Witch's House Quest. Even after you finish the quest they still have them on their heads.
An Experiment bone, which differs from the usual bones dropped by Experiment No. 2, are rare drops used in the Rag and Bone Man quest. This bone cannot be buried.
When it attacks with Ranged, it throws the shrunk ogleroot that it has in its arm on its head. Furthermore, a shrunk ogleroot may also appear below you when it attacks with range, similar to how when you attack an enemy with a ranged attack, your ammunition will appear underneath it.