Mr. Mole is the tertiary antagonist in Thumbelina.
Mr. Mole is greedy, gluttonous, cynical, serious and self involved. He is also rather shy, as evidenced by how he discretly asks Mrs Fieldmouse to talk Thumbelina into marrying him instead of making himself a proposal.
Ms. Fieldmouse introduces Mr. Mole to Thumbelina and convinces him that she's from out of the ground and Ms. Fieldmouse and Thumbelina bought Mr. Mole some corn cakes to try, he digs in the basket with his hands and gobbles gluttonously and he talks about how he went up but it was too bright for him, forcing him back to his tunnels where they are "dark and decent". Ms. Fieldmouse and Mr. Mole tell Thumbelina to tell and sing him a sad story. Mr. Mole tells a story about how he found a seemingly dead bird that got into his tunnel, Thumbelina and Ms. Fieldmouse were shocked and Thumbelina knew the bird named Jacquimo who got injured and is saved and healed by Thumbelina. Mr. Mole needed a word with Ms. Fieldmouse that he has a meeting to take a wife and Mr. Mole asked her to persuade Thumbelina to marry him so she can keep him company and tell him stories, Ms. Fieldmouse is shocked but agrees and Mr. Mole offers her a gold coin for her reward handsomely.
In the morning at Mr. Mole's Wedding, Thumbelina sadly approaches the Mole but thinks of her true love, Fairy Prince Cornelius. but she gets distracted by a Reverend Rat The priest who asks her that Thumbelina does take Mr. Mole to be her husband, but Thumbelina answers "Never!" She tells him that she cannot marry Mr. Mole and she don't love him. The Crowd gasp in alarm, Grundel Toad crashes the roof down to the ground, Thumbelina kicks Grundel Toad's Leg and runs away, Mr. Mole shouts "After Her!" and brings his guests as an angry mob to go after Thumbelina, after the duel of Grundel Toad and Cornelius, Mr. Mole continues to try to catch Thumbelina, but Thumbelina opens an exit and climbs out of the hole while the jewels and coins tumbles down towards to the Mole and his mobs and they scream in panic and run away.
At the end of the film Mr Mole and Ms Fieldmouse are seen married at the end of the credits