The most common and most likely answer to this crossword clue is the 7 letter word WARTHOG
I've seen this crossword clue in The Daily Telegraph
W
A
R
T
H
O
G
More clues leading to the result WARTHOG
- Creature on the Serengeti developing a growth
- Wild pig‘s growth affected eating acorns, primarily
- African native‘s wife painting house close to Johannesburg
- Animal fighting unsettled Goth
- Strange growth, a sight one may see on safari
- Animal with a growth that looks horrible
- Beast with a growth that’s deformed
- Animal developed a growth
- A growth disfigured an ugly beast
Buddy explains!

The straight part
We know that "Animal with a growth that looks horrible" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case animal with a growth that looks horrible = warthog.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WARTHOG mean?
WARTHOG noun- A wild pig of the genus Phacochoerus, native to Africa.
- A nickname for the A-10 Thunderbolt II air support warplane