Hammer came across, catching everyone (6)
I believe the answer is:
mallet
'hammer' is the definition.
(mallet is a kind of hammer)
'came across catching everyone' is the wordplay.
'came across' becomes 'met' ('meet' can be a synonym of 'come across').
'catching' indicates putting letters inside.
'everyone' becomes 'all' (I've seen this before).
'met' placed around 'all' is 'MALLET'.
(Other definitions for mallet that I've seen before include "Wooden hammer used in croquet" , "Croquet stick" , "It's used in croquet and polo" , "An auctioneer's wooden hammer" , "Small wooden hammer" .)