If you select some text and make it bold, and your selection contains an inline template, that template will disappear in the editor, and will be replaced with two snowmen (☃☃) once you move the cursor (and in the wikitext diff, regardless of whether you move the cursor).

Real life example in production:

1. Edit en:Vancouver in VisualEditor
2. Select the phrase "a resort community 125 km (78 mi) north of the city"
3. Make it bold. The text "125 km (78 mi)" disappears, and you see "a resort community north of the city"
4. Move the cursor. Two snowmen appear where the text "125 km (78 mi)" had been. You now see "a resort community ☃☃ north of the city"
5. Click "Publish changes", then "Review your changes". In the wikitext diff, you'll see that a resort community {{convert|125|km|abbr=on}} north of the city is changed to '''a resort community ☃☃ north of the city'''. This happens regardless of whether or not you do step 4.

Minimal example: https://www.mediawiki.org/wiki/User:Roan_Kattouw_(WMF)/Snowman_templates