Possible Clues:

• Hard worm taken by gannet, an insectivore
• Prince to go back round the border and become an urchin
• Urchin
• Hard boundary, hard to go over - it's prickly
• Spiny animal
• Cut the head off the little beast and you're left with a side of bacon, it seems
• Mr. Pricklepants in 'Toy Story 3,' e.g
• Animal ending in both two corners?
• Avoid commitment to someone selfish - a prickly creature
• Crawl into water, good animal