As an adjective mushroomlike is
having the form or characteristics of a mushroom.
As adjectives the difference between mushroom and mushroomlike
is that mushroom
is having characteristics like those of a mushroom, for example in shape or appearance, speed of growth, or texture while mushroomlike
is having the form or characteristics of a mushroom.
As a noun mushroom
is any of the fleshy fruiting bodies]] of [[fungus|fungi typically produced above ground on soil or on their food sources (such as decaying wood).
As a verb mushroom
is to grow quickly to a large size.