“Jesus said to them.
‘Go!’
Thus,
The demons came out.
They entered the swine.
The whole herd
Rushed down
The steep bank
Into the sea.
They perished in the waters.”
καὶ εἶπεν αὐτοῖς Ὑπάγετε. οἱ δὲ ἐξελθόντες ἀπῆλθον εἰς τοὺς χοίρους· καὶ ἰδοὺ ὥρμησεν πᾶσα ἡ ἀγέλη κατὰ τοῦ κρημνοῦ εἰς τὴν θάλασσαν, καὶ ἀπέθανον ἐν τοῖς ὕδασιν.
All three synoptic gospels, Mark, chapter 5:13 and Luke, chapter 8:33, and Matthew here, have Jesus cast out the demons into the herd of pigs nearby, with slight nuances in each story. Jesus then accommodated these evil spirits. He told them to leave the humans and go into the swine or pigs (καὶ εἶπεν αὐτοῖς Ὑπάγετε.). Then the demons left the humans (οἱ δὲ ἐξελθόντες) and entered the herd of pigs (ἀπῆλθον εἰς τοὺς χοίρους ἀπῆλθον εἰς τοὺς χοίρους). This herd then rushed down a steep bank into the sea (καὶ ἰδοὺ ὥρμησεν πᾶσα ἡ ἀγέλη κατὰ τοῦ κρημνοῦ εἰς τὴν θάλασσαν) where they died in the water (καὶ ἀπέθανον ἐν τοῖς ὕδασιν). There is one problem, pigs can swim, so some might have survived. Perhaps the unfamiliarity of this Jewish authors with pigs may have led to this harsh ending. Anyway, the pig herd, without a particular size here, ran into the sea off a steep bank.