a giant rat

• 4678, -923, 45 (3 of 8 spawns here)
• 3916, 15, 45 (seen once) (1 of 2 spawns here)
• 2720, -323, 46 (seen once)
• 2413, -299, 29 (seen once)
• 1203, 269, 0 (seen once)
• 216, 637, -2 (seen once)
• -56, -108, -2 (seen once)
• 2940, 347, 43 (seen once)
• 1338, -668, 19 (seen once)
• 11, -871, -2 (seen once)
• -56, -921, -2 (seen once) (1 of 2 spawns here)
• 4650, -903, 45 (seen once) (1 of 5 spawns here)
• 358, -6, 1 (seen once)
• 249, 373, -2 (seen once) (1 of 2 spawns here)
• 4570, 305, 16 (seen once)
• 3328, -37, 13 (seen once)
• 458, 306, -2 (seen once)
• 139, -791, -2 (seen once)
• 13, -1018, -2 (seen once)
• 4273, 306, -3 (seen once) (1 of 2 spawns here)
• 4256, 3, 36 (seen once)
• 4516, -287, 44 (seen once)
• 369, 82, 6 (seen once)
• 4413, -126, -38 (seen once)
• 4103, 227, 12 (seen once)
• 2372, 452, 27 (seen once)
• 486, -802, 26 (seen once) (1 of 2 spawns here)
• 197, 270, -2 (seen once) (1 of 2 spawns here)
• 181, -517, -2 (seen once)
• 2727, -522, 4 (seen once)

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.