These are past tense verbs/past participles. When a base word ends with a ‘short’ vowel then one consonant, we double the last consonant before adding the suffix ‘ed’. This preserves the vowel sound: a as in canned (not caned), e as in hemmed (not hemed), i as in shinned (not shined), o as in lobbed (not lobed), u as in shunned (not shuned). We don’t double consonants after unstressed vowels (opened not openned).

Base word ends with double consonantDouble last consonant of base word before adding ed
buzzed
culled
dolled
dulled
felled
fizzed
fuzzed
gulled
hulled
jazzed
jelled
lolled
lulled
mulled
razzed
rolled
shelled
tolled
welled
yelled
bagged
banned
begged
bobbed
bogged
bugged
canned
chugged
dabbed
dimmed
dobbed
dubbed
fanned
fibbed
fobbed
gagged
gummed
gunned
hammed
hemmed
hogged
hugged
hummed
jabbed
jammed
jigged
jogged
lobbed
logged
lugged
manned
mobbed
mugged
nabbed
nagged
panned
penned
pigged
pinned
rammed
ribbed
rigged
robbed
rubbed
sagged
shammed
shinned
shunned
sinned
sobbed
summed
sunned
tabbed
tagged
tanned
thinned
tinned
tugged
wagged