The last thing to give you warts? (5)
I believe the answer is:
straw
'the last thing' is the definition.
(I've seen this in another clue)
'give you warts?' is the wordplay.
'warts' anagrams to 'STRAW'.
Though, I'm not sure how the anagram is indicated.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for straw that I've seen before include "Thin tube; yellow" , "Thatching material" , "Dried stalks; yellow" , "corny stuff" , "politician" .)