Solution: The Very Hungry Caterpillar

Written by Ethan

First fill out the slitherlink and crossword clues. The crossword clues are in alphabetical order to aid in identification.
The next step is to put these words into the slitherlink grid. You can treat the slitherlink you've created like a fill-in, lightly hinted by "ate so much" (because you're putting words inside of the caterpillar/slitherlink). One possible break-in is to note the long line of 13 empty triangles from the top middle to the bottom right, and that CHOCOLATECAKE is also 13 letters. There are two directions CHOCOLATECAKE can go in, however, if you put the word from bottom to top, there is no 3 letter word that can fit in the bottom right (CH? or ?HC). Therefore, CHOCOLATECAKE must be placed from top to bottom. The rest of the grid can be filled from this main branch.

The highlighted letters spell MCCAFE LATTE, what the caterpillar drank.

Crossword clueAnswer
Curly hair in a rounded shape (4)AFRO
Nathan ___, Dutch soccer player (3)AKE
French words that come before "carte" or "mode" (2, 1)ALA
In addition to (4)ALSO
Change repeatedly between options (9)ALTERNATE
Unit of current (3)AMP
Pikachu's trainer (3)ASH
Titan who holds the heavens (5)ATLAS
Symbols in Twitter handles (3)ATS
Roman god of corn (5)CERES
A sweet piece of what the very hungry caterpillar ate on Saturday (9, 4)CHOCOLATECAKE
Quietly laugh to oneself (7)CHUCKLE
Obtain, barely (3)EKE
Ending for east, west, north, or south (3)ERN
First two words of Jeremiah 29:11 (3, 1)FORI
Waste time frolicking (6)FRIVOL
Department in hospital that provides intensive care (3)ICU
"___ the thick of it" - Backyardigans (4)INTO
Edible lens-shaped legumes (7)LENTILS
Test for future lawyers (4)LSAT
Westernmost landlocked African country (4)MALI
Lead singer of the Rolling Stones (4)MICK
South American root veggie (3)OCA
Not online (7)OFFLINE
Mabuse on Strictly Come Dancing (3)OTI
Slowly cooked soup (4)STEW
Parts of music that are sung (6)VOCALS