You can cast the spell web, a number of times equal to your proficiency bonus (wis) 

Your dexterity increases by 2, your wisdom increases by 1. However, -1 to charisma.

Tieflings mature at the same rate as humans but live a few years longer.

Arachne's are big. Your size is large.

Your base walking speed is 30 feet.

Thanks to your infernal heritage, you have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You have weakness to fire damage.

Proficiency of one skill of your choice from: stealth, intimidation, or perception.

You can speak, read, and write Common and undercommon