In the deep recesses of your programming you find instructions to a long forgotten and unfinished update that is available to you and your brethren. After initiating the download you gain access to the following features(Must be a warforged, forged variant, or have a mechanical body):

• You gain the ability to configure your body into a medium sized, metallic version of a creature. To be able to configure you must first: deal the final blow to a creature and then take a long rest with the creatures corpse. You can configure into the creature twice per day. The amount of time spent transformed is a equal number of hours to your player level. For the most part your stats and abilities mirror the creature, excluding health. 
• You may only have one creature creature configuration at any given time. If you choose to switch your creature configuration into a different creature, you must take a long rest and follow the above steps.
• When transformed you can choose to drop your items onto the floor to be picked up or choose to store them inside your mechanical body.

Unfortunately, due to the unfished state of update, you gain the following adverse effects:

• Due to the adaptive nature of your updated body, your metal plating has thinned and your organic portions have thickened. Your CON modifier is decreased by 1.
• When transformed you must make a INT saving throw every time it is your turn. DC being 10 + INT Modifier. If failed you fall victim to your integrated creatures instincts(It is up to the DM or DND lore to determine how you react). If successful then you may do your turn as normal.
• While you may be able to configure into just about any creature, you must keep in mind a few restrictions: You can not fly or swim even if the creature you configured into can, you are still made of metal(and organic parts) so you can not preform any abilities that are too far removed from what is reasonable(intangibility, teleportation, mind reading etc.),  and you remain just about the same size.