Where does the water weird from a Weird Tank go when it emerges?

Question

I'm trying to figure out how the water weird from a weird tank emerges from the tank and how it should be represented on a standard grid.

The description of the weird tank magic item (Princes of the Apocalypse, page 223) says:

A water weird is contained within the tank. While wearing the tank, you can use an action to open it, allowing the water weird to emerge. The water weird acts immediately after you in the initiative order, and it is bound to the tank.

This part is pretty clear to me: the weird remains inside the tank until summoned, and the source of water for the weird is the water within the tank.

Therefore, the weird cannot leave the vicinity of the tank, per the water weird's Water Bound trait (Monster Manual, page 299):

Water Bound. The water weird dies if it leaves the water to which it is bound or if that water is destroyed.

All fine so far. To me, this means that the water weird must occupy the same space as the tank. Since the water weird cannot fly, this means that the owner must remove the tank and place it down on a space separate from themselves (to avoid drowning in it) and the weird would then occupy a 2x2 square with one square containing the tank. It shouldn't be able to move from this square unless another source of water is available.

Does that sound right?

Answer 1

The Water Weird is in the Weird Tank at all times.

Remember that the Weird Tank is a:

... ten-gallon tank of blown glass and sculpted bronze with a backpack-like carrying harness fashioned from tough leather.

As you correctly point out:

... it is bound to the tank.

It cannot leave the tank without the tank being destroyed.

The Water Weird can emerge from the tank after you use an action to open it. It then remains in your space (as long as you are wearing the backpack).

It does not need to be placed down, or into another source of water, the Weird Tank is its source of water.

The Water Weird can only drown a target it makes a melee weapon attack on, and constricts them.

The Water Weird can only drown a target it uses the Constrict action on. If you were wearing the Weird Tank, and you got into this situation, you would presumably just telepathically command the Water Weird to retract instead of letting it drown you.