The phrase "off-the-wall" can often be used to describe something that is unusual or unexpected. However, if you're looking for other words to use in its place, there are a variety of options to choose from. For example, you could describe something as bizarre, eccentric, or quirky. Alternatively, you might use the synonyms unusual, weird, or unconventional. Other possible options include outlandish, far-out, or zany. Ultimately, the word you choose will depend on the specific context and the tone you want to convey. Whether you opt for "off-the-wall" or one of its many synonyms, you can be sure you're describing something that's a little bit out of the ordinary.