Hello Rollin,

Milkweed Tussock Moth Caterpillars — MSU Extension Perspective

I identified this as a Milkweed Tussock Caterpillar (Euchaetes). More information at this link:
Not just for monarchs! Milkweed is a vital food source for milkweed tussock moth caterpillars - Gardening in Michigan

Milkweed tussock moth caterpillars (Euchaetes egle), also called milkweed tiger moths, are native insects that rely exclusively on plants in the milkweed family (Asclepias spp.) and related dogbanes (Apocynum spp.) for food. They are not harmful to milkweed plants — even when they consume large amounts of foliage, the plants recover and regrow, and the caterpillars do not kill the plants.

Life Cycle and Behavior
Egg stage: Females lay dozens of pale gray eggs on the undersides of milkweed leaves in June.
Early instars: Off-white larvae with a bristly appearance and shiny black heads feed together in groups, skeletonizing leaves while avoiding latex-rich veins.
Later instars: Develop dense tufts of black, white, and orange/yellow hairs, giving them a striking, warning coloration.
Feeding habits: They grow through several molts (instars), eventually reaching up to 35 mm in length Wikipedia. They feed on both young and older milkweed shoots, sometimes avoiding competition with monarch caterpillars for younger leaves.
Adults: Soft gray moths with yellow abdomens and black dots; they use tymbal organs to emit ultrasonic clicks to deter bats.

Ecological Role
These caterpillars are specialist herbivores that have evolved to tolerate milkweed’s toxic cardiac glycosides, which they retain in their bodies to deter predators. They are part of a healthy insect community and contribute to biodiversity in milkweed habitats.

Management and Safety
No pesticide control is recommended by MSU Extension — the caterpillars are native and do not cause permanent plant damage.
If you want to protect milkweed for monarchs, you can hand-pick caterpillars, but wear gloves to avoid irritation from their urticating hairs.
Letting them feed is encouraged if you have enough milkweed, as it supports another native species and maintains ecosystem balance.

In summary: Milkweed tussock moth caterpillars are a normal, beneficial part of milkweed ecosystems. They are not harmful to plants, and their presence is a sign of a healthy milkweed habitat.

I hope this helps!