Large stripy creature losing head, biting old Trojan priest (7)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

This is where I ran out of GK, and I was not much helped by the wordplay. I mean apart from that comedy burglar’s mask  and its tail is a RACOON (from which you detach the head) a stripy creature? A zebra, sure, and a tiger, and at a push a wasp. If you know this particular detail of the Troy story, you can surmise that the L comes from L(arge) and the inserted O from O(ld). Hm. Must watch the film again, but I’ll bet he’s not there.