Complex sentence: Sméagol sees him fondling it and as they both succumb to the Ring's power a squabble over turns into a fight that ends with Sméagol strangling his friend with his bare hands as he then pries the Ring from Déagol's clenched fist.
Split into simpler sentences: Sméagol sees him fondling it and as they both succumb to the Ring's power they begin to quarrel. Sméagol strangles his friend with his bare hands and pries the Ring from Déagol's clenched fist.