Deadly Boots

3 times per long rest, these boots may be activated
When activated, they leave a trail of toxic goo in
each 5 foot square you step into for the remainder
of your turn. Anything that starts or ends its turn
in the gloop takes 3D6 fire damage. Anything
that passes through the sludge must make an
acrobatics saving throw DC16 to leap over the
muck or else take 1D10 damage and lose half its
movement for the round.
The boots protect the wearer from their effects.
By your polluting powers combined!