Tinker is a tenth level spell. This means it cannot be copied down into a spellbook, and any spellcaster who uses it, no matter how powerful, will have to make a DC 20 spellcasting ability check to even attempt to use it. Tenth level spells are typically forbidden infamous magics long lost to time.

As part of the cost of casting this spell, you magically destroy another non-common, non-consumable magic item in your possession. Then you may attempt to create a specific magic item or construct you are familiar with. "Familiar" in this case would likely be an item or construct that was once in your possession, or the subject of a Legend Lore spell.

Deities and other planar rulers can prevent this spell from affecting items or constructs in their possession.

If you roll a natural 1 while using the item, or the copied construct ever rolls a natural 1, the copy melts into slag.