Exegesis:
kai ēnegkan auton pros auton ‘and they brought him (the boy) to him (Jesus).’
kai idōn auton ‘and when he saw him’: this phrase can be understood in three ways: (1) ‘when Jesus saw the boy’: although grammatically possible, this is improbable; (2) ‘when the boy saw Jesus’: among others, this is the interpretation of Bengel, Lagrange, Montgomery, Le Nouveau Testament. Version Synodale, and O Novo Testamento de Nosso Senhor Jesus Cristo. Revisdo Autorizada; in its favor should be noticed that idōn ‘seeing’ is masculine, agreeing in gender with auton ‘him’ of the previous verse (which goes back to ton huion mou ‘my son’ of v. 17); (3) ‘when the spirit saw Jesus’: although idōn ‘seeing’ is masculine and does not agree in gender with to pneuma ‘the spirit,’ neuter, in light of the masculine participles kraxas ‘shrieking’ and sparaxas ‘convulsing’ in v. 26 which are masculine and refer to the unclean spirit, it is probable that the subject of idōn ‘seeing’ is ‘the spirit’ (cf. also in 5.7-9, 11-12, the case of the Gerasene demoniac); this is the interpretation given by most commentators and translators, and probably should be preferred.
sunesparaxen (only here in Mark; cf. sparassō 1.26) ‘he pulled about,’ ‘he tore,’ ‘he convulsed.’
kai pesōn epi tēs gēs ekulieto aphrizōn ‘and he fell to the ground and rolled about, foaming (at the mouth).’
piptō (cf. 4.4) ‘fall,’ ‘fall down.’
epi tēs gēs (cf. 9.3) ‘on the ground.’
kuliomai (only here in the N. T.; cf. kulismos 2 Pet. 2.22) ‘to roll oneself,’ ‘twist about,’ ‘wallow.’
aphrizō (cf. 9.18) ‘foam at the mouth.’
Translation:
For spirit see 1.26, 32.
Note that it is the spirit which is said to see Jesus.
For convulsed see 1.26.
Fell … rolled … foaming may be treated as three coordinate verb expressions if the receptor language construction so requires, e.g. ‘he fell on the ground, he rolled about; he foamed at the mouth.’ For rolled Toraja-Sa’dan has a vivid expression referring to the wobbling to and fro of a sun hat that has been put down in a sloping position, hence ‘turning and tossing restlessly.’
Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on the Gospel of Mark. (UBS Handbook Series). New York: UBS, 1961. For this and other handbooks for translators see here .