off-the-wall
1. [ adjective ] conspicuously or grossly unconventional or unusual
Synonyms: eccentric bizarre freakish freaky outlandish outre flaky
Examples:

"restaurants of bizarre design--one like a hat, another like a rabbit" "famed for his eccentric spelling" "a freakish combination of styles" "his off-the-wall antics" "the outlandish clothes of teen

Related terms: unconventional