Dr Longfellow's Lavish Laboritorium

You create a 20ft by 20ft room in an unoccupied space you can see within range. The rooms outward appearance can be specified by you and any number of creatures (up to a maximum of 9 medium or smaller creatures) that you allow may enter the room through the door, provided there is space for them.

Inside the room is any equipment you will need to undertake a scientific or magical experiment you have in mind at the time of casting and that may fit within the rooms space and 1 spectral lab assistant whose appearance is chosen by the caster and can perform the actions any basic human can but cannot attack and is unable to leave the laboratory. The equipment can be multiple machines you need or 1 singular device/tool. For instance you could choose to have a work table against 1 wall and a set of shelves against another with useful components for potion creation or choose to have a large equipment set for deciphering runes on an item to determine its magical properties.

Any materials or objects which originated in the room disappear when the spell ends or when it is taken more than 10ft from the room. Any piece of the outer wall of the room that is removed disappears after it is taken more than 10ft from the room or when the spell ends. Each 5ft length of wall of the room has an AC equal to your spell save DC and 20HP. Once this HP is reduced to 0 that portion of the wall is destroyed however the lab and any equipment within will remain until the spell ends or until it is subsequently destroyed (this is at your DM's discretion depending on nature and type of equipment).