The Mechanical Spider is a LEGENDARY pet that is available from the Mechanical Egg found in the Tech World. This pet has a ~0.035% base chance of hatching. It can also be obtained from fusing.
The latest Pet Simulator X value list for Mechanical Spider can be found below:
💎 1,500 (1.5k)
💎 4,300 (4.3k)
💎 12,900 (12.9k)
💎 41,000 (41k)