a darkweed snake

• -142, -614, -27 (seen once)
• 587, 219, -51 (seen once)
• 844, 3334, -51 (seen once)
• 1001, -1700, -13 (seen once)
• 975, -348, -52 (seen once)
• -70, 2042, -52 (seen once) (1 of 4 spawns here)
• 385, 867, -51 (seen once)
• 937, 1013, -42 (seen once)
• 699, 393, -51 (seen once)
• 1062, -1546, -9 (seen once) (1 of 2 spawns here)
• 574, 702, -51 (seen once)
• -90, 3672, -49 (seen once) (1 of 2 spawns here)
• 518, 1440, -51 (seen once)
• -37, -1100, -51 (seen once) (1 of 2 spawns here)
• -136, 3703, -50 (seen once) (1 of 2 spawns here)
• 363, -1292, -50 (seen once) (1 of 2 spawns here)
• 899, -378, -51 (seen once)
• -315, 565, -51 (seen once)
• 957, -45, -51 (seen once)
• 1091, 628, 43 (seen once) (1 of 3 spawns here)
• 921, 3661, -51 (seen once)
• 798, 453, -51 (seen once)
• 215, 3608, -51 (seen once)
• 0, 0, 20275 (seen once) (1 of 17 spawns here)

As /loc gives them: Y, X, Z, the most used first; nearby spawns share a spot, and one seen in a single visit may be where the mob had been pulled to.