To the wolpertinger spectulations it is from a World of Warcraft event called brewfest in which you do a quest where you become drunk and get one of these as a pet, it is probably someone who plays World of Warcraft and Runescape pranking everyone who only plays Runescape.
57 Combat DMing anyone up to my Combat, higher PM me ingame No Running No Teleing No Protect Prayer(Others allowed) Show Inventory Before fight No Range/Mage Both Skulled These are all the rules I can think of on this post, PM me ingame for more details (Zekei1)